
#include <bits/stdc++.h>
#define TUBO 3.305785
#define EPS 1e-10
using namespace std;

double calc(int a, int b) {
    return(a * b / (double)TUBO);
}

int main(void) {
    int a, b;
    cin >> a >> b;
    printf("%.6f\n", calc(a, b));
    
    return(0);
}