Help me in solving LJAJAG32 problem

help
,
1

My issue

Time Limit Exceeded

My code

#include <stdio.h>

int main()
{
    int num1, num2, result;
    scanf("%d %d", & num1, & num2);
    result = GCD(num1, num2);
    printf("GCD: %d", result);
}
int GCD(int a, int b)
    {
        while (a != b)
        {
            if (a > b)
            {
                return GCD (a-b,b);
            }
else
            {
                return GCD (a,b-a);
            }
        }
        return a;
    }

Learning course: Learn C Programming
Problem Link: https://www.codechef.com/learn/course/rcpit-programming-c/RCPITLPC37/problems/LJAJAG32