Time Limit : sec, Memory Limit : KB

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.

1 ≤ a, b ≤ 109

Hint

You can use the following observation:

For integers x and y, if xy, 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