uses crt;
var n: longint;

function isPerfectNumber(n: longint): boolean;
var i, total: longint;
begin
    total:=0;

    for i:=1 to trunc(sqrt(n)) do
        if n mod i = 0 then
            begin
                if i * i = n then total:=total + i
                else total:=total + i + n div i;
            end;

    total:=total - n;
    if total = n then exit(true)
    else exit(false);
end;

begin
clrscr;
    randomize;
    n:=random(1001); // random number between 0 -> 1000

    if isPerfectNumber(n) then writeln(n, ' is a perfect number')
    else writeln(n, ' is not a perfect number');
readln;
end.

uses crt;
var i,n,s: integer;
begin
clrscr;
write ('nhap n: ');   readln (n);
for i:=1 to n-1 do
if n mod i=0 then s:=s+i;
if s=n then writeln (n,' la so hoan hao')
else write (n,' ko phai la so hoan hao');
readln;
end.