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 JAVA (judge verdict: Accepted)


import java.util.Scanner;

public class Main {
    static Scanner sc = new Scanner(System.in);
    public static void main(String[] args) {
        int x = sc.nextInt();
        int y = sc.nextInt();
        int result = 0;
        if(x > y){
            result = gcd(x, y);
        } else {
            result = gcd(y, x);
        }
        System.out.println(result);
    }

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