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 JavaScript (node.js v5.12) (judge verdict: Wrong Answer)

(function() {
    'use strict';

    var lines = [];
    require('readline').createInterface({
      input: process.stdin,
      output: process.stdout
    }).on('line', function(line) {
      lines.push(line);
    });
    process.stdin.on('end', function() {
      //lines.forEach(function(line) {
        //var tokens = line.split(' ').map(Number);
        //    console.log(tokens[0] + ' ' + tokens[1]);
      //}
      //)
      ;

    // ToDo start
      var N = parseInt(lines[0])
      var ans = 0

      var sqrtN = Math.floor(Math.sqrt(N))
      console.log(sqrtN)
      var ans = sqrtN * sqrtN

      for (var i=sqrtN;i<=N;i++){
        var test = i*i
        if(test <= N){
            ans = test
        }
      }

    console.log(ans)
      
//      console.log( Math.pow(parseInt(lines[0]),2) - parseInt(lines[1])  )
    // ToDo end

    });


})();