#include <bits/stdc++.h>
using namespace std;
long long read() {
  long long w = 0, f = 1;
  char c = ' ';
  while (c < '0' || c > '9') c = getchar(), f = c == '-' ? -1 : f;
  while (c >= '0' && c <= '9') w = w * 10 + c - 48, c = getchar();
  return w * f;
}
long long n;
signed main() {
  n = read();
  long long m = sqrt(n);
  if (m * m == n) return printf("%lld\n", m * 2), 0;
  if (m * (m + 1) >= n) return printf("%lld\n", m * 2 + 1), 0;
  printf("%lld\n", m * 2 + 2);
  return 0;
}
