#include<stdio.h>
int gcd(int a,int b){
    while(b! = 0){
        int temp = b;
        b= a%b;
        a=temp;
    }
return a;
}
int main(){
    int n,m;
    if(scanf("%d %d",&n,&m) !=2||n<=0||m<=0){
        printf("Invalid input\n");
}else{
    printf("%d\n",gcd(n,m));
}
return 0;
}