Submission

Score: 100

User: code

Problemset: มุมขวาบน

Language: cpp

Time: 0.002 second

Submitted On: 2025-11-29 16:21:49

#include <bits/stdc++.h>
using namespace std;
int main (){
    int num;cin>>num;
    int n=1;
    while (n*n-n+1<num){
        n+=2;
    }
    if (n*n-n-1==num){
        cout<<"-1";
    }else if (n*n-n-2>=num){
        n-=2;
        cout<<n*n-n+1;
    }else{
        cout<<n*n-n+1;
    }
    return 0;
}