#include <iostream> using namespace std; //欧几里得算法 int GCD(int a, int b) { if (a == 0) { return b; } else if (b == 0) { return a; } else { return GCD(b, a % b); } } int main() { int a, b; while (scanf("%d %d", &a, &b) != EOF) { int x = GCD(a, b); cout << x; } }