#include <bits/stdc++.h>
using namespace std;
long long int A[1000001];
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int t = 1;
  while (t--) {
    long double n, k;
    cin >> n >> k;
    long double zz = 180 / n;
    zz = zz * 3.14159265 / 180;
    long double z = sin(zz);
    long double r1 = k * z;
    long double r2 = r1 / (1 - z);
    cout << fixed << setprecision(9) << r2;
  }
  return 0;
}
