#ifdef LOCAL111
#else
	#define NDEBUG
#endif
#include <bits/stdc++.h>
const int INF = 1e8;
using namespace std;

#define endl '\n'
#define ALL(a)  (a).begin(),(a).end()
#define SZ(a) int((a).size())
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define RFOR(i,a,b) for (int i=(b)-1;i>=(a);i--)
#define REP(i,n)  FOR(i,0,n)
#define RREP(i,n) for (int i=(n)-1;i>=0;i--)
#define RBP(i,a) for(auto& i : a)
#ifdef LOCAL111
	#define DEBUG(x) cout<<#x<<": "<<(x)<<endl
	template<typename T> void dpite(T a, T b){ for(T ite = a; ite != b; ite++) cout << (ite == a ? "" : " ") << *ite; cout << endl;}
#else
	#define DEBUG(x) true
	template<typename T> void dpite(T a, T b){ return; }
#endif
#define F first
#define S second
#define SNP string::npos
#define WRC(hoge) cout << "Case #" << (hoge)+1 << ": "
#define rangej(a,b,c) ((a) <= (c) and (c) < (b))
#define rrangej(b,c) rangej(0,b,c)
template<typename T> void pite(T a, T b){ for(T ite = a; ite != b; ite++) cout << (ite == a ? "" : " ") << *ite; cout << endl;}
template<typename T> bool chmax(T& a, T b){if(a < b){a = b; return true;} return false;}
template<typename T> bool chmin(T& a, T b){if(a > b){a = b; return true;} return false;}

typedef long long int LL;
typedef unsigned long long ULL;
typedef pair<int,int> P;
typedef pair<LL,LL> LP;

void ios_init(){
	cout.setf(ios::fixed);
	cout.precision(12);
#ifdef LOCAL111
	return;
#endif
	ios::sync_with_stdio(false); cin.tie(0);	
}

const double EPS = 1e-7;

int main()
{
	ios_init();
	int p0, q;
	while(cin >> p0 >> q){
		// p0 /= 100;
		// q /= 100;
		double ans = 1./3;
		unordered_map<int,double> dp;
		dp[p0] = 1./3;
		REP(hoge,10000){
			RBP(e,dp){
				// DEBUG(e.F);
				ans += e.S*(e.F/100./2+(1-e.F/100.)/3);
			}
			// DEBUG(ans);
			unordered_map<int, double> dpp;
			RBP(e,dp){
				dpp[max(0,e.F-q)] += 1./2*(e.F/100.)*e.S;
				dpp[min(100,e.F+q)] += 1./3*(1-e.F/100.)*e.S;
			}
			dp = dpp;
			// double t1, t2;
		}
		cout << ans << endl;
	}
	return 0;
}