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: Accepted)

#include <iostream>
#include <algorithm>
using namespace std;

signed main() {
  ios::sync_with_stdio(false);
  cin.tie(0);

  int n; cin >> n;
  int ans = 0;
  int tmp;
  for(int i = 1; i*i <= n; ++i) {
    ans = max(ans, i*i);
    tmp = i;
  }
  cout << ans << '\n';
  return 0;
}