uses crt;

var a,b,c,d:integer;

const e=100;

begin

write('nhap so KW moi:');readln(a);

write('nhap so KW cu:');readln(b);

c:=a-b;

writeln('So KW tieu thu moi thang la:',c);

if c<=e then d:=c*500 else d:=e*500+(c-e)*1000;

writeln('Tong tien dien la:',d);

readln;

end.

Uses crt;
Var
    cu,moi,tieu,gia,muc: LongInt;
Begin
    clrscr;
    write('Nhap chi so KW cu: '); readln(cu);
    write('Nhap chi so KW moi: '); readln(moi);
    tieu:=moi-cu;
    writeln('So KW tieu thu la: ',tieu);
    muc:=100;
    if tieu<=muc then gia:=tieu*500
        else gia:=muc*500+(tieu-muc)*1000;
    writeln('Tong tien dien phai tra la: ',gia);
    readln;
End.