#include <bits/stdc++.h>
#define ll long long

using namespace std;

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int a, b;
    cin >> a >> b;
    double ret = 100 - 1.0 * b / a * 100;
    printf("%.10f",ret);

    return 0;
}



#include <bits/stdc++.h>

#define N 1000000
#define MAX 1000000000
#define E 0.00000001
#define MOD 1000000007
#define INF 0x3f3f3f3f
#define LEFT(x) (2 * x)
#define RIGHT(x) (2 * x + 1)
#define PAR 0
#define IMPAR 1

using namespace std;

long long pf[N+1];
bool radical[N+1];

void solve(){
	
	int l, r; cin >> l >> r;

	memset(radical, true, sizeof(radical));

	long long ans = 0;
	for (long long i = 2; i <= r; i++) {

		if (pf[i] == 0) {
			for (long long j = i; j <= r; j += i) {
				pf[j]++;
			}
			for (long long j = i*i; j <= r; j += i*i) {
				radical[j] = false;
			}
		}

		long long cur = (r/i) - ((l-1)/i);

		if (radical[i]) {
			if (pf[i]%2) ans += cur * (cur - 1);
			else ans -= cur * (cur - 1);
		}
	}

	for (int i = max(l, 2); i <= r; i++) {
		ans -= (r-i)/i*2;
	}

	cout << ans << endl;

}

int main(){

	solve();

	return 0;
}