#include <algorithm>
#include <cstdio>
#include <functional>
#include <iostream>
#include <cfloat>
#include <climits>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <time.h>
#include <vector>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> i_i;
typedef pair<ll, int> ll_i;
typedef pair<double, int> d_i;
typedef pair<ll, ll> ll_ll;
typedef pair<double, double> d_d;
struct edge { int u, v; ll w; };

#define rep(i, N) for (int i = 0; i < N; i++)

ll MOD = 1000000007;
ll _MOD = 1000000009;
double EPS = 1e-10;

double solve(int x, double P) {
	return (double)x / 2 / P;
}

int main() {
	int x, p; cin >> x >> p;
	double P = p / 100.0;
	double ans;
	if (x % 2 == 0) ans = solve(x, P);
	else ans = 1 + P * solve(x - 1, P) + (1 - P) * solve(x + 1, P);
	printf("%.15f\n", ans);
}
