C :

#include<stdio.h>
#define CHANGE(a,b) printf("%d %d\n",b,a);
int main()
{
  int a,b;
  scanf("%d%d",&a,&b);
  CHANGE(a,b);
  return 0;
}

C++ :

#include <iostream>
using namespace std;
int main()
{
    int a,b;
    cin>>a>>b;
    cout<<b<<' '<<a<<endl;
    return 0;
}

Pascal :

var a,b:longint;
begin
  readln(a,b);
  writeln(b,' ',a);
end.