#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int Mod=998244353;
 
void solve() {
   int n;
   cin >> n;
   int ans=0;
   unordered_map<int,int> seen;
 
   for(int i=0;i<n;i++){
        int a;
        cin >> a;
        if(seen.find(a)==seen.end()) ans++;
        seen[a]=1;
   } 
 
   cout << ans << "\n";
}
 
int main(){ 
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
 
    int t;
    cin >> t;
    while (t--) solve();
 
 
    return 0;
}
 

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