http://cthbstalpha.blogspot.com/2016/05/ZJa024.html

ZJa024.cpp

#include<iostream>
using namespace std ;

int gcd(int a ,int b ){
    if (b==0)return a ;
    return gcd(b,a%b) ;
}

int main(){
    int a ,b ;

    while (cin >> a >> b ){
        cout << gcd(a,b) <<endl ;
    }
}