#include <stdio.h>
int main(){
	long int n, g, v;
	double ans;

	scanf("%ld %ld %ld", &n, &g, &v);
	n = n / 5;
	g = g * n;
	ans = (double)g / (double)v;
	printf("%.15f\n", ans);

	return 0;
}