#include<iostream>
#include<fstream>
#include<sstream>
#include<string>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<ctime>
#include<stack>
#include<queue>
#include<set>
#include<map>
#include<vector>
#include<list>
#include<algorithm>
#include<utility>
#include<complex>
#include<functional>
using namespace std;


#define input_init stringstream ss; string strtoken, token; istringstream is
#define input_line  getline(cin, strtoken);is.str(strtoken);is.clear(istringstream::goodbit)
#define input_token(num) ss.str(""); ss.clear(stringstream::goodbit); getline(is, token, ','); ss << token; ss >> num

double t[] = { 2, 3, 5, 7, 11, 13 };
double s[] = { 4, 6, 8, 9, 10, 12 };

int p, c;
double e = 0;
void func1(double val,int n){
	if (n == c){
		e += val;
		return;
	}
	for (int i = 0; i < 6; i++){
		func1(val*(s[i] / 6.0), n + 1);
	}
}
void func2(double val,int n){
	if (n == p){
		func1(val, 0);
		return;
	}
	for (int i = 0; i < 6; i++){
		func2(val*(t[i]/6.0),n+1);
	}
}
int main(void){
	cin >> p >> c;
	func2(1, 0);
	printf("%.10f\n");
	return(0);
}