Program tong_cac_so;
USES CRT;
Var N,i: Integer;
S: longint;
Begin
Write('Nhap so N = '); Readln(N);
S:=0;
If (N mod 3=0; N mod 5=0) then write (Thoa man tinh tong cua N) else write (Khong thoa man khong tinh tong N);
For i:=1 to N do S:=S+i;
Writeln ('Tong cua ',N,' so chia het cho 3 va 5 S=';S);
Readln
End.
Chúc bn hc tốt^^