/* -*- coding: utf-8 -*-
 *
 * 3037.cc:  No.3037 繝医げ繝ｫ繝医げ繝ｫ繝医げ繝ｫ! - yukicoder
 */

#include<cstdio>
#include<cmath>
#include<algorithm>

using namespace std;

/* constant */

/* typedef */

using ll = long long;

/* global variables */

/* subroutines */

/* main */

int main() {
  ll n;
  scanf("%lld", &n);

  int m = sqrtl((long double)n + 0.5);
  printf("%d\n", m);

  return 0;
}