#include<stdio.h>
int main() {
    int n,m;
    scanf("%d %d", &n,&m);
    
    if(n<0 || m<0) {
        printf("Invalid input");
        return 0;
    }
    while(m!=0){
        int temp = m;
        m = n%m;
        n = temp;
    }
    printf("%d",n);
}
  return 0;
}