Problem:
Greatest Common Divisor

Write a program which finds the greatest common divisor of two natural numbers a and b

Input

a and b are given in a line sparated by a single space.

Output

Output the greatest common divisor of a and b.

Constrants

1 ≤ a, b ≤ 109

Hint

You can use the following observation:

For integers x and y, if x ≥ y, then gcd(x, y) = gcd(y, x%y)

Sample Input 1

54 20

Sample Output 1

2

Sample Input 2

147 105

Sample Output 2

21

Solution in JavaScript (judge verdict: Accepted)

var input = require('fs').readFileSync('/dev/stdin', 'utf8');
var Arr=(input.trim()).split("\n");
Arr.forEach(function(v){
   var arr=v.split(" ").map(Number);
   var m=Math.max(arr[0],arr[1]);
   var n=Math.min(arr[0],arr[1]);
   while(n!=0){
      var N=n;
      n=m%n;
      m=N;
   }
   console.log(m);
});