#include <bits/stdc++.h>
typedef long long ll;
const int maxn = 1005;
int a[maxn], dp[maxn];
int main()
{
  ll n; scanf("%lld", &n);
  
  ll x = (ll)sqrt(n);
  
  ll y = x * x;
  n -= y;
  
  std::cout << 2 + x + n << "\n";
  
  return 0;
}