#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, s, e) for (int i = (int)(s); i < (int)(e); ++i)
#define all(a) (a).begin(),(a).end()

int main() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    
    int N;
    cin >> N;
    
    set<pair<int, int>> S;
    rep(i, 0, N) {
        int A, B;
        cin >> A >> B;
        if (S.count({A, B})) {
            cout << "Yes\n";
            return 0;
        }
        S.insert({A, B});
    }
    cout << "No\n";
}