C++ :

#include<iostream>

using namespace std;

int main()
{
	int a,b;
	cin>>a>>b;
	cout<<"xiang"<<":"<<(b-a*2)/(4-2)<<" "<<"niao"<<":"<<(a*4-b)/(4-2)<<endl;
	return 0;
}

Pascal :

var n,m,a,b:longint;
begin
  readln(n,m);
  for a:=1 to n do
      begin
        b:=n-a;
        if a*2+b*4=m then writeln('xiang:',b,' niao:',a);
      end;
end.