Contest1472/K.cpp

#include<bits/stdc++.h>
using namespace std;
int main(){
    int n;cin>>n;
    int m=sqrt(n);
    int left=m*m,right=(m+1)*(m+1);
    if(m-left<right-m)cout<<left<<endl;
    else cout<<right<<endl;
     
    return 0;
}