#include <stdio.h>
 int gcd(int a, int b){
     if (b == 0)
        return a;
    return gcd(b, a % b):
 }
 
int main(){
    int a, b;
    scanf("%d", &a);
    scanf("%d", &b);
    
    if ( a <= 0 || b <= 0){
        printf("Inavlid input");
        return 0;
    }
    
    if (a < b) {
        int temp = a;
        a = b;
        b = temp;
    }
    printf("%d", gcd(a,b));
    return 0;
}