#include<stdio.h>
int  max3(a, b, c) {
    if (a > b && a > c)
        return a;
    else if (b > a && b > c)
        return b;
    else return c;
}
int main() {
    int a = 0, b = 0, c = 0;
    scanf("%d %d %d", &a, &b, &c);
    float ma = (float)max3(a + b, b, c) / (max3(a, b + c, c) + max3(a, b, b + c));
    printf("%.2f", ma);
    return 0;
}