bài 1.
program baigiai;
uses crt;
var a,b,s:longint;
begin
clrscr;
writeln('nhap a, b '); readln(a,b);
if (a mod 2)<>0 and (b mod 2)<>0 then s:=s+a+b
  else s:=a*b;
write(s);
readln; 
end.
**************
bài 2.
program baigiai;
uses crt;
var n,dem,s,i:longint;
begin
clrscr;
writeln('nhap n '); readln(n);
for i:=1 to n do
if (i mod 2)=0 then dem:=dem+1
 else s:=s+i;
write(dem,', ',s);
readln;
end.