#include <bits/stdc++.h>
#define rep(x, to) for (int x = 0; x < (to); x++)
#define REP(x, a, to) for (int x = (a); x < (to); x++)
#define EPS (1e-14)
#define _PA(x,N) rep(i,N){cout<<x[i]<<" ";}cout<<endl;
#define _PA2(x,H,W) rep(i,(H)){rep(j,(W)){cout<<x[i][j]<<" ";}cout<<endl;}

using namespace std;

typedef long long ll;
typedef pair<int, int> PII;
typedef pair<ll, ll> PLL;
typedef complex<double> Complex;
typedef vector< vector<int> > Mat;

int p, q;
char done[105][10005];
double dp[105][10005];

double dfs(int r, int depth) {
	if (depth < 0) {
		return 0;
	}
	if (done[r][depth]) {
		return dp[r][depth];
	}

	double a, b;
	double pp = r / 100.0;

	// use
	a = pp / 2.0 + pp / 2 * dfs(max(0, r - q), depth - 1);
	// not use
	b = (1.0 - pp) / 3.0 + (1.0 - pp) / 3.0 * dfs(min(100, r + q), depth - 1);

	done[r][depth] = 1;
	return dp[r][depth] = a + b;
}

void solve() {
	printf("%.12f\n", 1.0 / 3.0 + 1.0 / 3.0 * dfs(p, 10000));
}

int main() {
	cin >> p >> q;
	solve();
	return 0;
}