#include <bits/stdc++.h>

#define ff first
#define ss second
#define mp make_pair

using namespace std;

double dp[10005][10005];
double prob[4][4][4];

double f(int a, int b){
    if(a == 1) return 0;
    if(b == 0) return 1;
    if(dp[a][b] != -1) return dp[a][b];
    double ret = 0;
    if(a > 3){
        if(b >= 3)
            ret = (prob[3][3][3]*f(a,b-3) + prob[3][3][2]*f(a-1,b-2) + prob[3][3][1]*f(a-2,b-1) + prob[3][3][0]*f(a-3,b));
        else if(b == 2)
            ret = (prob[3][2][2]*f(a,b-2) + prob[3][2][1]*f(a-1,b-1) + prob[3][2][0]*f(a-2,b));
        else
            ret = (prob[3][1][1]*f(a,b-1) + prob[3][1][0]*f(a-1,b));
    }
    else if(a == 3){
        if(b >= 3)
            ret = (prob[2][3][2]*f(a,b-2) + prob[2][3][1]*f(a-1,b-1) + prob[2][3][0]*f(a-2,b));
        else if(b == 2)
            ret = (prob[2][2][2]*f(a,b-2) + prob[2][2][1]*f(a-1,b-1) + prob[2][2][0]*f(a-2,b));
        else
            ret = (prob[2][1][1]*f(a,b-1) + prob[2][1][0]*f(a-1,b));
    }
    else{
        if(b >= 3)
            ret = (prob[1][3][1]*f(a,b-1) + prob[1][3][0]*f(a-1,b));
        else if(b == 2)
            ret = (prob[1][2][1]*f(a,b-1) + prob[1][2][0]*f(a-1,b));
        else
            ret = (prob[1][1][1]*f(a,b-1) + prob[1][1][0]*f(a-1,b));
    }
    return dp[a][b] = ret;
}

int main () {
    int n,m;

    prob[1][1][1] = (double)15/36;
    prob[1][1][0] = (double)21/36;

    prob[1][2][1] = (double)55/216;
    prob[1][2][0] = (double)161/216;

    prob[1][3][1] = (double)225/1296;
    prob[1][3][0] = (double)1071/1296;

    prob[2][1][1] = (double)125/216;
    prob[2][1][0] = (double)91/216;

    prob[2][2][2] = (double)295/1296;
    prob[2][2][1] = (double)420/1296;
    prob[2][2][0] = (double)581/1296;

    prob[2][3][2] = (double)979/7776;
    prob[2][3][1] = (double)1981/7776;
    prob[2][3][0] = (double)4816/7776;

    prob[3][1][1] = (double)855/1296;
    prob[3][1][0] = (double)441/1296;

    prob[3][2][2] = (double)2890/7776;
    prob[3][2][1] = (double)2611/7776;
    prob[3][2][0] = (double)2275/7776;

    prob[3][3][3] = (double)6420/46656;
    prob[3][3][2] = (double)10017/46656;
    prob[3][3][1] = (double)12348/46656;
    prob[3][3][0] = (double)17871/46656;

    scanf("%d%d", &n,&m);

    for(int i = 0; i <= n; i++)
        for(int j = 0; j <= m; j++) dp[i][j] = -1;


    printf("%.4lf\n", f(n,m));
    return 0;

}