#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
const long long inf = 922337203685477;
const long long mininf = -922337203685477;
const long long nax = 0;
long long n;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  cin >> n;
  long long ans = inf;
  for (long long i = 1; i * i <= n; i++) {
    long long l = 1, r = 1e9, ret = 0;
    while (l <= r) {
      long long mid = (l + r) / 2;
      if (mid * i >= n) {
        ret = mid;
        r = mid - 1;
      } else {
        l = mid + 1;
      }
    }
    ans = min(ans, ret + i);
  }
  cout << ans << '\n';
}
