#include<bits/stdc++.h>
using namespace std;

int p;
int q;
long double dp[2][102];
vector<double> v;
int main(){
	cin >> p >> q;
	double ans = 1.0 / 3.0;
	dp[0][p] = 1.0 / 3.0;
	int siz = v.size();
	bool flag = false;
	double star = clock();
	while((clock()-star)/(double)(CLOCKS_PER_SEC)<1.8){
		for (int j = 0; j <=100; j++){
			if (1){
				//win
				long double P = j;
				P /= 100.0;
				ans += dp[flag][j] * P*1.0 / 2.0;
				//tie
				int nex_j = max(j-q,0);
				dp[flag^true][nex_j] += dp[flag][j] * P*1.0 / 2.0;
				//nothing
				P = (1.0 - P);
				ans += dp[flag][j] * P*1.0 / 3.0;
				nex_j = min(j + q,100);
				dp[flag^true][nex_j] += dp[flag][j] * P*1.0 / 3.0;
			}
			dp[flag][j] = 0;
		}
		flag ^= true;
	}
	printf("%.16f\n", ans);
	return 0;
}