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 C (judge verdict: Time Limit Exceeded)

#include <stdio.h>
int main(void) {
    int a, b, i, c, d, e, f, g;
    e = 1;
    
    

    scanf("%d %d", &a, &b);
    if(a > b) {
        f = a;
        a = b;
        b = f;
    }
    g = b % a;

    for(i = 1; i <= b; i++) {
        if(g % i == 0) {
            c = i;
         
            if(b % i == 0) {
            d = i;
        }
    }
        if(c == d) {
            e = c;
        }
    }

    printf("%d\n", e);
    return 0;
}