C :

#include<stdio.h>

int main()
{
	int a,b,c;
	a=9;
	b=20;
	c=a;
	a=b;
	b=c;
	printf("%d %d\n",a,b);
	return 0;
}

C++ :

#include<stdio.h>

int main()
{
	int a,b,c;
	scanf("%d%d",&a,&b);
    c=a;
	a=b;
    b=c;
    printf("%d %d",a,b);
    return 0;
}

Pascal :

var n,m:longint;
begin
  readln(n,m);
  writeln(m,' ',n);
end.