#include<bits/stdc++.h>
using namespace std;
using LL = long long;
using ULL = unsigned long long;
#define rep(i,n) for(int i=0; i<(n); i++)

LL GCD(LL a, LL b) { return b ? GCD(b, a % b) : a; }

double F(LL x) {
	return pow(1. / double(x), double(x));
}

int main() {
	cout << fixed << setprecision(10);

	double ans = 0.;

	LL A, B; cin >> A >> B;
	A = abs(A); B = abs(B);

	if (A != 0 && B != 0) {
		LL G = GCD(A, B);
		A /= G; B /= G;

		if (A % 2 == 1 && B % 2 == 1) {
			rep(x, 20) rep(y, 20) {
				if (x % G != 0 || y % G != 0) continue;
				if ((x + y) % 2 == 1) continue;
				ans += F(x + y + 2);
			}
		}
		else {
			rep(x, 20) rep(y, 20) {
				if (x % G != 0 || y % G != 0) continue;
				ans += F(x + y + 2);
			}
		}
	}
	else if (A == 0 && B == 0) {
		ans = 0.25;
	}
	else {
		if (B == 0) swap(A, B);
		rep(x, 20) rep(y, 20) {
			if (x % B != 0 || y % B != 0) continue;
			ans += F(x + y + 2);
		}
	}

	cout << ans << endl;

	return 0;
}