✔ 문제

✔ 해결

class Solution {
  public long solution(long n) {
    long answer = -1, number = 0;
    
    for(long i = 0; i <= n; i++) {
      if(i * i == n && i == i) {
        number = i;
        break;
      }
    }
    
    if(number > 0) {
      answer = (number + 1) * (number + 1);
    }
    
    return answer;
  }
}