BATDEN C++

#include <bits/stdc++.h>
using namespace std;
long long k,a,p,mid;

void chat(long long l,long long r)
{
    while(l<=r)
    {
        mid = (l+r)/2 ;
        if(mid-int(sqrt(mid))>=k)
        {
            p=mid;
            r=mid-1;
        }
        else l=mid+1;
    }
}
int main()
{
    freopen("batden.inp","r",stdin);
    freopen("batden.out","w",stdout);
    cin >> k ;
    chat(k,k*2);
    cout << p;
}