#include <bits/stdc++.h>
using namespace std;

int main()
{
    long long n;
    cin>>n;
    int a =1,c=0;
    long long x;
    while(x<=n){
        x=1;
        x = a*a;
        if (x<=n) c++;
        x = a*a+1;
        if (x<=n) c++;
        a++;
    }

    cout<<c;
}