参考答案：

#include<iostream>
#include<cmath>
using namespace std;
int ans;
int main()
{
    int a, b;
    cin >> a >> b;
    for (int i = 1; i <= a; ++i)
    {
        if (a % i == 0)
        {
            if (b % i == 0) ans = max(ans, i);
        }
    }
    cout << ans << endl;

    return 0;
}