#include<iostream>
using namespace std;

void swap(int &a, int b){
	int temp = a;
	a = b;
	b = temp;
}

int main(){
	int x = 500;
	int y = 900;

	cout << x << " " << y << endl;
	swap(x, y);
	cout << x << " " << y << endl;
	return 0;
}