{"trustable":false,"sections":[{"title":"","value":{"format":"PLAIN","content":"组合数公式 C(m,n)\u003dm!/((m-n)! * n!) , 现在请你计算C(p,q) /C(r,s).\n\n\n\n\nInput\n\n每行包含四个非负整数,分别给出值p,q,r和 s, 所有数字都小于10000 且p\u003e\u003dq and r\u003e\u003ds\n\nOutput\n\n输出一行包含5位小数精度的实数,保证结果不大于100000000\n\n\n\n\nSample Input\n\n10 5 14 9\n93 45 84 59\n145 95 143 92\n995 487 996 488\n2000 1000 1999 999\n9998 4999 9996 4998\n\nSample Output\n\n0.12587\n505606.46055\n1.28223\n0.48996\n2.00000\n3.99960"}}]}