#include <bits/stdc++.h>
using namespace std;

using ll = long long;

bool chmin(auto &a, auto b) { return a > b ? a = b, true : false; }
bool chmax(auto &a, auto b) { return a < b ? a = b, true : false; }

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int N;
    cin >> N;
    vector<string> S(N), T(N);
    for (int i = 0; i < N; i++) cin >> S[i] >> T[i];
    string ans = "Yes";
    for (int i = 0; i < N; i++) {
        bool okS = true, okT = true;
        for (int j = 0; j < N; j++) {
            if (i == j) continue;
            okS = okS && (S[i] != S[j]) && (S[i] != T[j]);
            okT = okT && (T[i] != S[j]) && (T[i] != T[j]);
        }
        if (!okS && !okT) ans = "No";
    }
    cout << ans << endl;
}