Найти количество различных чисел в последовательности

program ex;
uses crt;
var a:array[1..10]of integer;
i,n:integer;
Begin clrscr;
writeln('vvedite razmernost massiva');readln(n);
for i:=1 to n do
begin
write('a[',i,']=');readln(a[i]);
end;
for i:=1 to n do
if a[i]=0 then a[i]:=a[i+1];
for i:=1 to n do
a[n]:=0;
dec(n);
for i:=1 to n do
write(a[i],' ');
readln;
end.

program ex;
uses crt;
const n=10;
var mas:array[1..n] of string;
i,j,num:integer;
begin clrscr;
writeln('vvedite massiv');
for i:=1 to n do
begin write('m[',i,'] = ');readln(mas[i]);
end;
for i:=1 to n-1 do
for j:=i+1 to n do
if (mas[i]=mas[j]) then mas[i]:='duplicate';
writeln('rezultat:');
for i:=1 to n do
if mas[i]<>'duplicate' then inc(num);
writeln('V massive ',num,' razlichnih elementov:');
for i:=1 to n do
if mas[i]<>'duplicate' then write(mas[i],' ');
writeln;
readkey;
end.