{"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"}},{"title":"","value":{"format":"PLAIN","content":"Input\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"}},{"title":"","value":{"format":"PLAIN","content":"Output\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"}},{"title":"","value":{"format":"PLAIN","content":"Sample Input\n10 4 4 1\n93 45 84 59\nSample Output\n52.50000\n505606.46055"}}]}