/*
TASK:minitime
LANG:C++
*/
#include<iostream>
using namespace std;
int main()
{
    int n,i,min=110,b;
    cin>>n;
    for (i=2;i<n;i++)
    {
        b=i+n/i;
        if (n%i!=0) b++;
        if (b<min) min=b;
    };    
    if (min<n) cout<<min; else cout<<n;
    return 0;
}    
