There are 900 possible numbers:
1000, 1001, 1002, 1003, 1004, 1095, 1096, 1097, 1098, 1099,
1100, 1101, 1102, 1103, 1104, 1195, 1196, 1197, 1198, 1199,
1200, 1201, 1202, 1203, 1204, 1295, 1296, 1297, 1298, 1299,
1300, 1301, 1302, 1303, 1304, 1395, 1396, 1397, 1398, 1399,
1400, 1401, 1402, 1403, 1404, 1495, 1496, 1497, 1498, 1499,
1500, 1501, 1502, 1503, 1504, 1595, 1596, 1597, 1598, 1599,
1600, 1601, 1602, 1603, 1604, 1695, 1696, 1697, 1698, 1699,
1700, 1701, 1702, 1703, 1704, 1795, 1796, 1797, 1798, 1799,
1800, 1801, 1802, 1803, 1804, 1895, 1896, 1897, 1898, 1899,
1900, 1901, 1902, 1903, 1904, 1995, 1996, 1997, 1998, 1999,
2000, 2001, 2002, 2003, 2004, 2095, 2096, 2097, 2098, 2099,
2100, 2101, 2102, 2103, 2104, 2195, 2196, 2197, 2198, 2199,
2200, 2201, 2202, 2203, 2204, 2295, 2296, 2297, 2298, 2299,
2300, 2301, 2302, 2303, 2304, 2395, 2396, 2397, 2398, 2399,
2400, 2401, 2402, 2403, 2404, 2495, 2496, 2497, 2498, 2499,
2500, 2501, 2502, 2503, 2504, 2595, 2596, 2597, 2598, 2599,
2600, 2601, 2602, 2603, 2604, 2695, 2696, 2697, 2698, 2699,
2700, 2701, 2702, 2703, 2704, 2795, 2796, 2797, 2798, 2799,
2800, 2801, 2802, 2803, 2804, 2895, 2896, 2897, 2898, 2899,
2900, 2901, 2902, 2903, 2904, 2995, 2996, 2997, 2998, 2999,
3000, 3001, 3002, 3003, 3004, 3095, 3096, 3097, 3098, 3099,
3100, 3101, 3102, 3103, 3104, 3195, 3196, 3197, 3198, 3199,
3200, 3201, 3202, 3203, 3204, 3295, 3296, 3297, 3298, 3299,
3300, 3301, 3302, 3303, 3304, 3395, 3396, 3397, 3398, 3399,
3400, 3401, 3402, 3403, 3404, 3495, 3496, 3497, 3498, 3499,
3500, 3501, 3502, 3503, 3504, 3595, 3596, 3597, 3598, 3599,
3600, 3601, 3602, 3603, 3604, 3695, 3696, 3697, 3698, 3699,
3700, 3701, 3702, 3703, 3704, 3795, 3796, 3797, 3798, 3799,
3800, 3801, 3802, 3803, 3804, 3895, 3896, 3897, 3898, 3899,
3900, 3901, 3902, 3903, 3904, 3995, 3996, 3997, 3998, 3999,
4000, 4001, 4002, 4003, 4004, 4095, 4096, 4097, 4098, 4099,
4100, 4101, 4102, 4103, 4104, 4195, 4196, 4197, 4198, 4199,
4200, 4201, 4202, 4203, 4204, 4295, 4296, 4297, 4298, 4299,
4300, 4301, 4302, 4303, 4304, 4395, 4396, 4397, 4398, 4399,
4400, 4401, 4402, 4403, 4404, 4495, 4496, 4497, 4498, 4499,
4500, 4501, 4502, 4503, 4504, 4595, 4596, 4597, 4598, 4599,
4600, 4601, 4602, 4603, 4604, 4695, 4696, 4697, 4698, 4699,
4700, 4701, 4702, 4703, 4704, 4795, 4796, 4797, 4798, 4799,
4800, 4801, 4802, 4803, 4804, 4895, 4896, 4897, 4898, 4899,
4900, 4901, 4902, 4903, 4904, 4995, 4996, 4997, 4998, 4999,
5000, 5001, 5002, 5003, 5004, 5095, 5096, 5097, 5098, 5099,
5100, 5101, 5102, 5103, 5104, 5195, 5196, 5197, 5198, 5199,
5200, 5201, 5202, 5203, 5204, 5295, 5296, 5297, 5298, 5299,
5300, 5301, 5302, 5303, 5304, 5395, 5396, 5397, 5398, 5399,
5400, 5401, 5402, 5403, 5404, 5495, 5496, 5497, 5498, 5499,
5500, 5501, 5502, 5503, 5504, 5595, 5596, 5597, 5598, 5599,
5600, 5601, 5602, 5603, 5604, 5695, 5696, 5697, 5698, 5699,
5700, 5701, 5702, 5703, 5704, 5795, 5796, 5797, 5798, 5799,
5800, 5801, 5802, 5803, 5804, 5895, 5896, 5897, 5898, 5899,
5900, 5901, 5902, 5903, 5904, 5995, 5996, 5997, 5998, 5999,
6000, 6001, 6002, 6003, 6004, 6095, 6096, 6097, 6098, 6099,
6100, 6101, 6102, 6103, 6104, 6195, 6196, 6197, 6198, 6199,
6200, 6201, 6202, 6203, 6204, 6295, 6296, 6297, 6298, 6299,
6300, 6301, 6302, 6303, 6304, 6395, 6396, 6397, 6398, 6399,
6400, 6401, 6402, 6403, 6404, 6495, 6496, 6497, 6498, 6499,
6500, 6501, 6502, 6503, 6504, 6595, 6596, 6597, 6598, 6599,
6600, 6601, 6602, 6603, 6604, 6695, 6696, 6697, 6698, 6699,
6700, 6701, 6702, 6703, 6704, 6795, 6796, 6797, 6798, 6799,
6800, 6801, 6802, 6803, 6804, 6895, 6896, 6897, 6898, 6899,
6900, 6901, 6902, 6903, 6904, 6995, 6996, 6997, 6998, 6999,
7000, 7001, 7002, 7003, 7004, 7095, 7096, 7097, 7098, 7099,
7100, 7101, 7102, 7103, 7104, 7195, 7196, 7197, 7198, 7199,
7200, 7201, 7202, 7203, 7204, 7295, 7296, 7297, 7298, 7299,
7300, 7301, 7302, 7303, 7304, 7395, 7396, 7397, 7398, 7399,
7400, 7401, 7402, 7403, 7404, 7495, 7496, 7497, 7498, 7499,
7500, 7501, 7502, 7503, 7504, 7595, 7596, 7597, 7598, 7599,
7600, 7601, 7602, 7603, 7604, 7695, 7696, 7697, 7698, 7699,
7700, 7701, 7702, 7703, 7704, 7795, 7796, 7797, 7798, 7799,
7800, 7801, 7802, 7803, 7804, 7895, 7896, 7897, 7898, 7899,
7900, 7901, 7902, 7903, 7904, 7995, 7996, 7997, 7998, 7999,
8000, 8001, 8002, 8003, 8004, 8095, 8096, 8097, 8098, 8099,
8100, 8101, 8102, 8103, 8104, 8195, 8196, 8197, 8198, 8199,
8200, 8201, 8202, 8203, 8204, 8295, 8296, 8297, 8298, 8299,
8300, 8301, 8302, 8303, 8304, 8395, 8396, 8397, 8398, 8399,
8400, 8401, 8402, 8403, 8404, 8495, 8496, 8497, 8498, 8499,
8500, 8501, 8502, 8503, 8504, 8595, 8596, 8597, 8598, 8599,
8600, 8601, 8602, 8603, 8604, 8695, 8696, 8697, 8698, 8699,
8700, 8701, 8702, 8703, 8704, 8795, 8796, 8797, 8798, 8799,
8800, 8801, 8802, 8803, 8804, 8895, 8896, 8897, 8898, 8899,
8900, 8901, 8902, 8903, 8904, 8995, 8996, 8997, 8998, 8999,
9000, 9001, 9002, 9003, 9004, 9095, 9096, 9097, 9098, 9099,
9100, 9101, 9102, 9103, 9104, 9195, 9196, 9197, 9198, 9199,
9200, 9201, 9202, 9203, 9204, 9295, 9296, 9297, 9298, 9299,
9300, 9301, 9302, 9303, 9304, 9395, 9396, 9397, 9398, 9399,
9400, 9401, 9402, 9403, 9404, 9495, 9496, 9497, 9498, 9499,
9500, 9501, 9502, 9503, 9504, 9595, 9596, 9597, 9598, 9599,
9600, 9601, 9602, 9603, 9604, 9695, 9696, 9697, 9698, 9699,
9700, 9701, 9702, 9703, 9704, 9795, 9796, 9797, 9798, 9799,
9800, 9801, 9802, 9803, 9804, 9895, 9896, 9897, 9898, 9899,
9900, 9901, 9902, 9903, 9904, 9995, 9996, 9997, 9998, 9999