program Rec4;
{ recursive sum function example    }
{ exemplo de funcao soma recursiva }
{ Turbo Pascal 7 source        }
{ Free Pascal Source           }
{ Delphi Source                }
{ Joao Paulo Schwarz Schuler   }
{ http://www.schulers.com/jpss }


function RSum(X,Y:word):word;
begin

if X=0
   then begin
        if Y=0
           then RSum:=0
           else RSum:=RSum(X,Y-1)+1;
        end
   else RSum:=RSum(X-1,Y)+1;

end;

begin
Writeln(RSum(0,0));     { 0  }
Writeln(RSum(0,1));     { 1  }
Writeln(RSum(1,0));     { 1  }
Writeln(RSum(1,1));     { 2  }
Writeln(RSum(10,5));    { 15 }
end.