Câu trả lời:
uses crt;
var f,g:text;
n,i,m,k,j:integer;
a:array[1..10000] of integer;
const fi='BAI2.INP'; fo='BAI2.OUT';
begin
assign(f,fi); reset(f);
assign(g,fo); rewrite(g);
readln(f,n);
for i:=1 to n do
readln(f,a[i]);
for i:=1 to n do
begin
m:=a[i];
for j:=i+1 to n do
if odd(m+a[j])=false then k:=k+1;
end;
write(g,k);
close(f);
close(g);
end.