#include <iostream>

using namespace std;

void swap2 (int &val1, int &val2) {
    int temp = val1;
    val1 = val2;
    val2 = temp;
  }

int main (void) {
  int x = 1;
  int y = 3;

  swap2(x, y);

  cout << x << y << endl;

  return 0;
}