#include <stdio.h>
#define WA double
WA WAWA(WA a, WA b, WA c){
	if(a > b && b > c) return a;
	else if(b > a && a > c) return b;
	else return c;
}
int main(){
	WA a, b, c;
	scanf("%lf %lf %lf", &a, &b, &c);
	WA fz = WAWA(a, b, c), fm1 = WAWA((a + b), b, c), fm2 = WAWA(a, b, (b + c));
	WA ans = fz * 1.0 / (fm1 * 1.0 * fm2);
	printf("%.3f", ans);
	return 0;
}