int main() {
int a, b;
cin >> a>>b;
int c;//定义一个空值
c = a;//把a的值给ca = b;//把b的值给a
b = c;//在把之前c的值放入b
cout << a << " "<< b;
return 0;
}
int a, b;
cin >> a>>b;
int c;//定义一个空值
c = a;//把a的值给ca = b;//把b的值给a
b = c;//在把之前c的值放入b
cout << a << " "<< b;
return 0;
}