#include <iostream> #include <vector> #include <algorithm> #include <map> #include <queue> #include <cstdio> #include <ctime> #include <assert.h> #include <chrono> #include <random> #include <numeric> #include <set> using namespace std; typedef long long int ll; typedef unsigned long long ull; int a[6]={1,2,3,4,5,6}; int b[6]={4,4,5,5,6,6}; mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count()); ll myRand(ll B) { return (ull)rng() % B; } int main(){ cin.tie(nullptr); ios::sync_with_stdio(false); int n,k; cin >> n >> k; int cnt=0; for(int i=0;i<1e6;i++){ int score=0; for(int i=0;i<n;i++){ score+=a[myRand(6)]; } int score2=0; for(int i=0;i<n;i++){ if(i<k)score2+=b[myRand(6)]; else score2+=a[myRand(6)]; } if(score2>score)cnt++; } printf("%.9f\n",(double)(cnt/1e6) ); }