program tong_chiahet_a_b;
uses crt;
var t,i,a,b,n:integer;
begin
clrscr;
write('Nhap n: '); readln(n);
write('Nhap a: '); readln(a);
write('Nhap b: '); readln(b);
t:=0;
for i:=1 to n do
if (i mod a=0) or (i mod b=0) then t:=t+i;
write('Tong cac so chia het cho ',a,' hoac ',b,' tu 1 den ',n,' la: ',t);
readln;
end.