#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
//#pragma GCC target("popcnt")
using namespace __gnu_pbds;
using namespace std;
using ordered_set = tree<int, null_type, less_equal<>, rb_tree_tag, tree_order_statistics_node_update>;
#define popcount __builtin_popcountll
#define all(a) (a).begin(), (a).end()
signed main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
int n; cin >> n;
set<int> s;
while (n--) {
int x; cin >> x;
s.insert(x);
cin >> x;
}
cout << s.size();
}
