C++ :

#include<iostream>
using namespace std;
int main(){
	int a,b,t;
	cin>>a>>b;
	if(a>b)t=b;
	else t=a;
	while(true)
	{
		if(a%t==0&&b%t==0){
			cout<<"yue:"<<t;
			break;
		}
		t--;
	}
	return 0;
}

Pascal :

var a,b,c:longint;
begin
  readln(a,b);
  if a>b then c:=b else c:=a;
  while (a mod c<>0) or (b mod c<>0) do c:=c-1;
  writeln('yue:',c);
end.