uva 10491

https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=1432

 

 

#include <stdio.h>

int main () {
    int a, b, c;
    while (scanf("%d%d%d", &a, &b, &c) == 3) {
        printf("%.5lf\n", (1.0 * a * b + b * (b - 1)) / (a + b - c - 1) / (a + b ));
    }
    return 0;
}