#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using mint = modint998244353;
//using mint = modint1000000007;
typedef long long ll;
typedef pair<ll, ll> P;
typedef tuple<ll, ll, ll> T;
template<typename T>bool chmax(T& a, const T& b) { if (a < b) { a = b;return true; } else { return false; } }
template<typename T>bool chmin(T& a, const T& b) { if (a > b) { a = b;return true; } else { return false; } }

const int di[] = { -1,0,1,0 };
const int dj[] = { 0,-1,0,1 };
const long long INF = 9223372036854775807;
const int inf = 1001001001;


int main(void) {
    int n; cin >> n;
    set<P> s;
    bool ok = false;
    for (int i = 0; i < n; i++) {
        int a, b; cin >> a >> b;
        if (s.count({ a,b }))ok = true;
        s.insert({ a,b });
    }
    cout << (ok ? "Yes" : "No") << "\n";
}
//overflow,out_of_range