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() {
 int a,b,c;

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

 while (b != 0)
  c = b;
  b = a%b;
  a = c;
 
 
 printf("%d\n", a);
 return 0;

}