uses crt;
var i,n,s,j,tam:integer;
a:array[1..100] of integer;
begin
clrscr;
write('nhap so luong go:');readln(n);
for i:=1 to n do
begin
 write('do dai cua khuc go thu ',i,' la:');
 readln(a[i]);
end;
for i:=1 to n-1 do
for j:=i+1 to n do
 if a[i]<a[j] then
 begin
  tam:=a[i];
  a[i]:=a[j];
  a[j]:=tam;
 end;
for i:=1 to n do
 if a[i]<>a[i+1] then s:=s+1;
write('so luong go co do dai khac nhau la:',s);
readln;
end.

#include <bits/stdc++.h>
using namespace std;
#define ll long long
int n, ans = 0;
vector <int > v;
int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);

    cin >> n;
    for (int i = 0; i < n; i++){
        int tmp; cin >> tmp;
        v.push_back(tmp);
    }
    sort(v.begin(), v.end());
    for (int i = 0; i < v.size(); i++){
        if (v[i] != v[i+1])
            ans++;
    }
    cout << ans << '\n';
    return 0;
}