Problem:
Score : 200 points

Problem Statement

Find the largest square number not exceeding N. Here, a square number is an integer that can be represented as the square of an integer.

Constraints

1 \leq N \leq 10^9

N is an integer.

Input

Input is given from Standard Input in the following format:

N

Output

Print the largest square number not exceeding N.

Sample Input 1

10

Sample Output 1

9

10 is not square, but 9 = 3 × 3 is. Thus, we print 9.

Sample Input 2

81

Sample Output 2

81

Sample Input 3

271828182

Sample Output 3

271821169

Solution in C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

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

int main() {
    int n; cin >> n;
    for (int i = 1; i < n; i++) {
        int tmp = i*i;
        if (tmp == n) {
            cout << (int)pow(i, 2) << endl;
        }
        else if (tmp > n) {
            cout << (int)pow(i-1, 2) << endl;
            return 0;
        }
    }
    
    return 0;
}