#include<iostream> // cin\cout\endl #include<cstdio> //scanf()\printf() #include<cstring> // strcpy()\strcat()\strcmp()\strlen()\memset() #include<cmath> //sqrt()\pow()\abs()\ceil()\floor()\max()\min() using namespace std; int main(){ long long a,b,c; cin>>a>>b; c=a%b; while(c!=0){ a=b; b=c; c=a%b; } cout<<b; return 0; }