#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <ctime>
#include <cstring>
using namespace std;

short a[23][23];
int n, m;
long timp()
{
    long nr = 0, t = 0;
    while(nr < n*m)
    {
        t++;
        int x = rand() % n;
        int y = rand() % m;
        if(a[x][y] == 2) nr--;
        else
            if(a[x][y] == 1) nr++;
        a[x][y] = (a[x][y]+1) % 3;
    }
    return t;
}
int main()
{
    freopen("minesweeper.in", "r", stdin);
    cin >> n >> m;
    double rez;
    for(int i = 1; i < 99999; i++)
        {
            rez += timp();
            memset(a, 0, n*m*sizeof(int));
        }
    FILE *f = fopen("minesweeper.out", "w");
    fprintf(f, "%20.5f",  rez / 99999);
    return 0;
}