#include <iostream>
using namespace std;
int main(){
  long long n;cin>>n;
  long long mn = 1;
  long long mx = 1000000001;
  while(mx-mn > 1){
    long long ce = (mn+mx)/2;
    if(ce*ce <= n)mn = ce;
    else mx = ce;
  }
  long long mn2 = 0;
  long long mx2 = n;
  while(mx2-mn2 > 1){
    long long ce = (mn2+mx2)/2;
    if(n/ce <= mn)mx2 = ce;
    else mn2 = ce;
  }
  cout << mn + mn2 << endl;
}