#include<bits/stdc++.h>
using namespace std;
#define F first
#define S second
#define mkp make_pair
#define MEM(x) memset(x,0,sizeof(x))
#define ALL(x) begin(x), end(x)
#define PH push
#define PB push_back
#define REP(i,N) for( int i = 0; i <(N); ++i )
#define FOR(i,a,b) for( int i = (a); i <= (b); ++i )
typedef long long ll;
typedef pair<ll,ll> pll;
typedef pair<int,int> pii;
template<typename T>
using V = vector<T>;
void solve() {
int N; cin >> N;
set< int > st;
REP(i,N) {
int x, e; cin >> x >> e;
st.insert( x );
}
cout<<st.size() <<'\n';
}
int main () {
int T=1;
#ifdef LOCAL
freopen( "input.txt", "r", stdin );
freopen( "output.txt", "w", stdout );
cin >> T;
#else
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#endif
while(T--) solve();
}
