#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); ++i)

using namespace std;

int main(){
    int n;
    cin >> n;
    
    vector<string>  s(n), t(n);
    rep(i, n) cin >> s[i] >> t[i];
    
    rep(i, n) {
        bool found = false;
        for (string x : {s[i], t[i]}) {
            bool ok = true;
            rep(j, n) if (j != i) {
                ok &= x != s[j] and x != t[j];
            }
            if (ok) found = true;
        }
        if (not found) {
            puts("No");
            return 0;
        }
    }
    
    puts("Yes");
      
    return 0;
}