This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#define Magic ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define tsts int t; cin >> t; while(t--)
#include <bits/stdc++.h>
using namespace std;
using lli = long long int;
using ull = unsigned long long int;
using ld = long double;
using str = string;
#define pb push_back
#define pf push_front
#define sz size()
#define bg begin()
#define ers erase
inline void debugMode() {
    #ifndef ONLINE_JUDGE
    freopen("in.txt", "r", stdin);
    freopen("out.txt", "w", stdout);
    #endif // ONLINE_JUDGE
}
int main(){
    Magic
    //debugMode();
    lli n;
    cin >> n;
    pair <lli, lli> x[n];
    set <lli> a;
    for (lli i = 0 ; i < n ; i++){
    	cin >> x[i].first >> x[i].second;
    	a.insert(x[i].first);
    }
    cout << a.sz;
}
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢀⣠⠤⢲⣦⡀⠀⣠⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣀⣀⣀⣠⠖⠚⠓⠒⠒⠲⠿⣍⣛⣻⣦⣷⢠⣻⣀⠤⠤⣀⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣠⠔⡿⠓⠲⠬⢥⡤⠤⠤⠤⠤⣤⣀⣀⣈⣻⣿⣿⠓⠉⣀⡤⠔⢶⣻⡆⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢀⣀⣤⢤⠞⠁⣼⠀⠀⠀⠀⠀⠀⠰⠶⢌⣽⡶⠟⢏⡁⢈⣉⣭⣷⡯⣝⠒⢦⣄⠙⠷⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⡾⣵⠿⣳⡟⠉⠉⠿⠀⠀⡀⠀⠀⣀⣀⣢⣾⣿⡚⠓⠒⠒⠒⠻⢿⣟⣧⡀⢠⣢⡻⠙⣄⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢀⡀⢿⣟⣲⢿⣷⢀⣤⣠⣄⣈⢿⣷⣤⣷⣻⡓⠒⠻⠭⢷⡄⠒⠲⢶⣦⣬⣻⣏⢦⡈⢿⣆⠘⡄⠀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢠⢖⣩⠷⢎⣙⣿⣿⣼⡼⣿⣟⣽⣻⢯⢿⠞⣌⠙⢳⡕⠀⠙⠲⣶⠤⢄⡠⣄⡈⠛⣿⣿⣧⢳⣌⢻⡆⡇⠀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠰⠗⠉⢀⣾⠟⠒⡿⣫⡿⡾⢫⢟⡏⠉⢸⡀⠑⢾⡆⢤⣻⣶⣤⣘⣲⣿⣶⡽⠿⣯⠲⣌⣇⢹⣷⣿⣆⠸⡇⠀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⠀⠀⡼⠀⣿⢣⣧⠋⣸⠀⣰⢀⣿⣆⠀⠰⣄⠙⣧⣨⣿⣿⣿⣯⣿⣦⠘⣷⡌⢻⡄⠿⣆⠟⣆⢇⠀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢀⣀⠀⠀⠀⠀⠀⠀⠀⠀⡇⡼⣹⠈⢣⠆⡇⣰⣻⣼⣿⣽⣷⣦⣹⣿⣟⣯⠉⠘⣿⠏⠃⠀⣷⣽⡿⣾⡹⣷⣹⣧⡈⢺⡀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣠⢾⠟⠉⠀⠀⠀⠀⠀⠀⠀⠀⣷⣱⣽⡀⢸⣆⢳⣿⣇⣷⡿⠖⠿⠷⢦⣙⣆⠩⡗⠀⠀⠀⠀⠀⡯⠿⠳⣟⠻⣽⣄⢧⠈⠳⣷⡀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⣸⡇⡏⠀⠀⠀⠀⠀⠀⠀⠀⠀⢀⣤⣿⣿⣷⣸⣿⡀⣿⣅⠛⠇⠀⠀⠀⠀⢈⠙⠂⠀⠀⠀⠀⠀⣸⣿⠀⢠⣜⢦⠘⢿⣮⣷⡀⠀⠙⢦⡀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⢯⣇⠙⢄⣀⠀⠀⠀⢀⣀⡠⣴⣾⣫⠵⠛⣿⣻⠿⣷⣹⣾⣷⡠⡀⠀⠀⠀⠻⠦⠀⣀⠔⠀⠀⣴⣿⣸⣧⡀⠳⣝⠳⢴⡙⢞⣏⠢⡀⠀⠹⡄⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⢀⣀⣀⣈⣻⣤⣀⠈⠉⠻⠿⢿⣺⣿⡵⣶⢶⣦⠀⠘⣿⢷⣾⢿⣿⡋⢙⣮⣄⡀⠀⠀⠉⠈⠀⠀⢀⢞⣿⣼⣿⣿⣿⣆⡀⠙⢦⣝⣮⠛⢷⡙⢆⠀⣷⠀⠀⠀⠀
///⠀⠀⠀⢠⡴⢟⣫⠤⠖⠒⠛⢛⣲⣿⣿⣿⠟⠋⢱⣿⣴⣷⣿⣹⢃⣀⣘⠃⢩⢿⣫⣥⣿⠧⢿⣿⣗⡶⣤⣄⣀⣴⣷⣻⣿⣿⠻⠘⣏⠛⢿⣦⣀⠱⢤⣉⡑⠛⠮⢿⣹⠀⠀⠀⠀
///⠀⢠⢖⠵⠊⠁⢀⡤⠖⣲⣿⣿⣟⣻⣿⣋⠀⠀⠈⢿⣿⡿⠟⣵⣿⣿⣿⣷⡏⠈⢿⡿⣷⣤⣼⢿⣿⣿⢶⣯⣭⣵⣾⢿⣿⠿⢦⡀⢹⠀⠈⣏⠉⠉⢻⣶⣯⡑⠦⣄⠈⠳⣄⠀
///⠀⠹⠁⠀⠀⣞⢁⡾⢽⣯⣝⣛⣛⣯⣭⣽⣿⣷⣶⣤⣤⣴⣿⣿⣿⣿⣿⣿⡀⣀⣼⣀⠈⠙⠛⠷⣾⡿⢿⡟⣿⠟⠁⣈⣥⡴⠾⠷⢾⡄⠀⣿⠀⠀⠈⢇⠘⣿⣤⣀⠑⢦⡘⢧⠀
///⠄⠀⠀⠀⠀⠈⠻⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⡿⢿⡿⠛⣻⢏⡽⣯⡄⠘⣏⣿⡏⠈⠙⠓⠶⣤⣀⠀⠙⢿⣿⡇⢀⡿⠋⠁⠀⢀⣀⣸⡇⠀⣟⣀⠀⠀⠀⠙⠃⣿⡎⠑⣤⡙⣌⡇
///⠀⠀⠀⠀⠀⠀⠀⠙⢿⣿⣿⣿⣿⣿⣿⣿⡥⣖⡯⠖⢋⣡⡞⣼⣿⠀⠀⢹⣿⣷⠀⠀⣀⡀⠀⠉⠻⣦⠀⢿⣿⡿⠁⣠⡶⠟⠋⠉⠹⣆⣸⣿⣿⠀⣀⡤⣤⡀⣿⠇⠀⢸⠳⡜⡇
///⠀⠀⠀⠀⠀⠀⠀⠀⣈⣿⣿⣿⣿⣿⣿⣏⢿⣗⠒⠊⠉⢸⠁⡿⡏⠀⢀⣿⡿⣁⠤⢶⣿⣽⡆⠀⠀⠘⢷⡈⠉⣡⠾⠋⠀⠀⣠⣆⢠⣿⣿⣿⡟⢀⣷⠒⢺⣧⡏⠀⠀⢸⠀⢹⣹
///⠀⠀⠀⠀⠀⠀⡠⢪⠟⡽⠙⢶⣾⣿⣿⣿⣷⡻⣦⡀⠀⠀⢣⣇⡇⢀⡞⣸⠏⠁⠀⠀⡇⢻⡀⠀⠀⣾⣶⡟⣿⣥⡄⠀⠀⢠⣇⣼⡶⣿⣿⠋⣸⣾⣷⣚⣽⡟⠀⠀⠀⣏⠀⡼⣿
///⠀⠀⠀⠀⢀⠎⡴⣣⣾⠟⣡⠞⢹⡿⣿⢿⣿⣿⣿⣷⣄⠀⠈⠻⡹⣼⠀⣿⡄⠀⠀⠀⠉⠻⣷⡀⠀⠙⠿⠇⣿⠿⠇⠀⠀⢠⡿⠋⢇⢹⣟⢷⠫⣿⣟⡿⠋⠀⠀⣠⣾⢞⡜⠁⡿
///⠀⠀⠀⠀⡼⡼⣵⠏⡏⣰⠃⠀⢾⡇⠈⠻⣿⣮⡉⠹⣿⣧⣄⡀⠙⣇⠀⠸⣿⣄⡀⠀⠀⠀⠈⢉⣧⡴⠀⠠⡄⣀⡤⠤⠴⠋⠁⠀⠈⢻⣿⣾⣤⡿⠋⠀⠀⠀⣉⣽⠿⠋⠀⣰⠃
///⠀⠀⠀⠀⣿⣽⠋⠀⡇⡇⠀⠀⠘⣷⢠⣶⢮⣻⣿⣦⠈⠛⠙⠹⣷⠘⢦⣤⣿⣳⣭⣑⣒⣒⣺⣿⢿⣀⣀⣀⣿⣧⣀⣀⣀⡤⠴⠒⣶⣿⣏⣾⡿⠁⠀⠀⠀⠉⠉⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⢻⡏⠀⠀⢳⣇⠀⠀⠀⠈⠈⣿⣾⣿⣿⣮⣿⣦⠀⠀⢿⣶⡫⣿⣿⣿⣿⣿⡹⣯⣊⠁⠉⠉⠉⠉⢙⣮⣷⣶⡤⣤⣶⣿⣿⣟⣾⢿⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠸⣿⣦⡀⠀⠙⠦⠀⠀⢀⣼⠿⣽⣿⣯⣷⣼⡷⢾⣻⣾⣿⠞⢿⢻⡷⠻⣿⣏⡙⢝⣻⡾⡖⠒⣻⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⡟⣎⠣⣀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠈⠁⠀⠀⠀⠀⣴⣋⣉⣩⣿⣿⢿⣟⣷⣾⣯⡟⢱⡇⠀⠘⣿⠣⡀⣈⣻⣿⣿⣿⣷⣷⣶⣿⣿⣟⠋⡿⣹⣿⣿⣿⣿⢟⣏⠺⠿⠶⠭⠷⠂⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⢰⣿⣿⣿⣿⣿⣿⣿⢹⣮⣾⣿⡿⢋⣶⢸⡇⠀⠀⠈⢷⡑⠈⢻⣟⠛⠛⠿⠋⠙⠓⣭⣿⣹⣵⣿⣿⣿⣿⣿⠈⠻⣷⣄⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⠙⢟⣛⡭⠶⢾⡿⠃⠀⠀⢸⢹⣾⣇⠀⠀⠀⠀⠻⣟⣿⡏⠀⠀⠀⠀⢰⣿⣿⢿⡇⣿⣿⣿⣿⣟⡏⠀⠀⠀⠉⠙⠓⠒⠂⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢠⡟⠀⠀⠀⢰⣿⢸⣿⢿⡀⠀⠀⠀⠀⢸⣿⣣⠀⠀⠀⢠⣿⡟⣷⣾⣿⢿⣿⣿⣿⣿⡇⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢀⣿⠁⠀⠀⠀⠘⡿⡿⢿⣏⣧⠀⠀⠀⢀⣾⣿⠿⠀⢀⣴⣿⣿⢿⡹⡇⣿⠈⣿⣿⡟⣾⠇⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢸⣿⡇⠀⠀⠀⠀⢳⢧⠈⢿⣿⠀⠀⢀⣼⣿⠕⠁⣠⣾⡿⣻⠏⠀⢹⣹⣿⣆⣿⣿⣿⣿⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣾⣿⣷⠀⠀⠀⠀⠈⣏⢧⠀⢻⣧⠶⣋⠿⠋⣀⣾⣟⣿⠞⠁⠀⠀⠀⢯⣿⣿⣿⣿⣿⡏⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢻⣿⣿⣇⠀⠀⠀⠀⠸⡜⣆⠈⢷⣿⠀⢠⣾⣿⠟⢻⡏⠀⠀⠀⠀⠀⠘⣿⣿⠏⣿⣿⠃⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢸⡻⣿⣿⣦⡀⠀⠀⠀⢧⠘⣆⠈⢷⠒⠛⢻⡿⠄⠘⣧⠀⠀⠀⠀⠀⢰⣷⣹⠀⠙⣿⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⣷⣝⣿⣿⣷⣄⠀⠀⠈⢇⠸⡄⠈⣇⠀⠀⢻⣆⠀⠘⣇⠀⠀⣠⣾⣽⢹⡟⠀⢰⣷⡄⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢻⣾⢻⠙⢿⣿⡇⠀⠀⠈⢧⢳⠀⢸⡀⠀⠀⢻⣆⠀⢻⡄⢠⣿⣯⣽⣓⣧⣤⠾⢹⣿⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢸⣿⣼⡇⠀⠙⣿⠀⠀⠀⠈⢏⢧⠀⣇⠀⠀⠀⢻⣆⠀⢷⠘⣿⣮⡻⣿⠁⠀⢀⣯⣿⡄⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢿⣿⣧⡀⠀⠀⠀⠀⠀⠀⠘⡾⡄⢸⠀⠀⠀⠈⢻⣆⠈⢷⣷⣾⣟⣻⣶⣿⡿⠛⢿⣷⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⣿⣿⣿⣦⣀⠀⠀⠀⠀⠀⢳⣇⠘⡆⠀⠀⠀⠀⠻⣶⢺⡏⢹⡟⠀⠉⠁⠀⠀⠀⢩⣍⠙⡆⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠸⣟⣿⣿⣿⣧⠀⢀⣤⣤⡸⣸⠀⡇⠀⠀⠀⠀⠀⠙⣿⣷⢡⣿⣶⣄⠀⠀⣄⠀⣦⣍⠙⢳⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠹⡿⢿⡙⠿⠀⢸⡟⢲⣷⡿⡄⢿⠀⠀⠀⠀⠀⠀⠘⣏⢸⣇⣍⢻⣷⣀⢻⣦⣤⣌⡙⣦⡇⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠹⣯⢷⠀⠀⠸⡇⠀⢿⣧⡇⢸⠀⠀⠀⠀⠀⠀⠀⣼⢸⣿⣯⠀⣿⣿⣷⣝⣿⣻⣿⣼⣷⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢻⣎⣧⠀⠐⣇⠀⠘⣽⣿⡸⡆⠀⠀⠀⠀⠀⠀⠈⠋⠈⠻⣼⣿⢶⢿⣿⣯⡻⣿⣿⣾⣷⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢻⡼⡆⠀⣿⡀⠀⣿⢿⡇⢷⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠘⣿⣾⢧⠈⠙⠿⣮⠟⠉⠙⢦⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⢿⢻⢠⣿⡇⠀⠹⣄⢳⣜⡆⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢹⡏⠪⠳⢤⣄⣀⠀⠀⠀⠈⢣⠀⠀⠀⠀⠀⠀⠀⠀⠀
///⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠘⣎⣿⡟⡇⠀⠀⠈⢻⣿⣷⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢳⡄⠀⠀⠀⠙⢧⡀⢀⡄⠈⡇⠀⠀⠀⠀⠀⠀⠀⠀
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