#include <iostream>
#include <cstdio>
#include <cassert>
#include <cstring>
#include <vector>
#include <valarray>
#include <array>
#include <queue>
#include <set>
#include <unordered_set>
#include <map>
#include <unordered_map>
#include <algorithm>
#include <cmath>
#include <complex>
#include <random>

using namespace std;
using uint = unsigned int;
using ll = long long;
using ull = unsigned long long;
template<class T = ll> constexpr T TEN(int n) {return (n==0)?1:10*TEN<T>(n-1);}
int bsr(int x) { return 31 - __builtin_clz(x); }

using R = double;

int p0, q;


R calc(int p, int dps = 0) {
    if (dps >= 100) {
        return 0;
    }
    p = max(0, p); p = min(100, p);
    R ans = 0;
    static R dp[101][101];
    static bool used[101][101];
    if (used[p][dps]) return dp[p][dps];
    used[p][dps] = true;
    R pr = R(p)/100;
    // use
    {
        ans += pr * 1.0/2;
        ans += pr * 1.0/2 * calc(p-q, dps+1);
    }
    // not use
    {
        ans += (1-pr) * 1.0/3;
        ans += (1-pr) * 1.0/3 * calc(p+q, dps+1);
    }
    return dp[p][dps] = ans;
}

int main() {
    cin >> p0 >> q;
    R ans = 1.0 / 3 + 1.0/3 * calc(p0);
    printf("%.20lf\n", ans);
    return 0;
}