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)

function gcd( x, y )
{
  if( 0 == y ) {
    return x;
  } else {
    return gcd( y, x%y );
  }
}

var input = '';
var readable = process.stdin;
readable.resume();
readable.setEncoding( 'utf-8' );
readable.on( 'data', function( chunk ) {
  var nums =  chunk.split( ' ' ).map( Number );
  console.log( gcd( Math.max( nums[0], nums[1] ), Math.min( nums[0], nums[1] ) ) );
});