#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
#else
  #define Debug(...) void(0)
#endif
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  int n;
  cin >> n;
  long double ans = 0;
  for (int i = 1;; ++i) {
    long double x = 1.0L / powl((long double) i, n);
    if (x < numeric_limits<long double>::epsilon()) break;
    ans += x;
  }
  cout << fixed << setprecision(15) << ans << '\n';
  return 0;
}