#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for (int i = 0; i< (n); ++i)
#define repi(i, a, b) for (int i = (a); i < (b); ++i)
#define all(x) (x).begin(), (x).end()
#define fore(i, a) for(auto &i:a)
using ll = long long;
//https://yukicoder.me/problems/no/3196

//b:999999797, 999999883, 1000000007, 1000000009, 2147483647, 2147771771
struct roling_hash{
	vector<ll> H, B;
	ll n, b, mod;
	string s;
	roling_hash(string s_,ll b_, ll mod_){
		s = s_;b = b_; mod = mod_;
		n = s.size()+1;
		H.assign(n,0);
		B.assign(n,0);
		H[0] = 0;
		B[0] = 1;
		repi(i, 1, n){
			H[i] = (b*H[i-1]%mod+s[i-1])%mod;
			B[i] = B[i-1]*b%mod;
		}
	}

	ll get_hash(ll l,ll r){
		return (H[r+1] - B[r-l+1]*H[l]%mod+mod)%mod;
	}

	ll get_hash(string t){
		ll res=0;
		ll sz = t.size();
		rep(i, sz){
			res += B[sz-1-i]*t[i]%mod;
			res %= mod;
		}
		return res;
	}
};
long long random_large_ll(ll m, ll M) {
	static std::random_device rd;
	static std::mt19937_64 gen(rd());

	std::uniform_int_distribution<long long> dist(m, M);
	return dist(gen);
}
int main() {
	ll n; cin >> n;
	map<ll,ll> id;
	vector<ll> s(n), t(n);
	roling_hash RH("____________________", 233123, 1000000007);
	bool flag = true;
	rep(i, n){
		string a, b;
		cin >> a >> b;
		s[i] = RH.get_hash(a);
		t[i] = RH.get_hash(b);
		if(id.count(s[i]))id[s[i]]++;
		else id[s[i]] = 1;
		if(id.count(t[i]))id[t[i]]++;
		else id[t[i]] = 1;
	}
	rep(i, n){
		if(id[s[i]] > 1 && id[t[i]] > 1)flag = false;
	}
	if(flag)cout << "Yes" << endl;
	else cout << "No" << endl;
}