#include <iostream>
#include <algorithm>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <numeric>
#include <bitset>
#include <cmath>
#include <limits>
#include <array>

static const int MOD = 998244353;
using ll = long long;
using uint = unsigned;
using ull = unsigned long long;
using namespace std;

template<class T> constexpr T INF = ::numeric_limits<T>::max() / 32 * 15 + 208;


int main() {
    int n;
    cin >> n;
    set<pair<int, int>> s;
    for (int i = 0; i < n; ++i) {
        int a, b;
        scanf("%d %d", &a, &b);
        if(s.count({a, b})) {
            puts("Yes");
            return 0;
        } else {
            s.insert({a, b});
        }
    }
    puts("No");
    return 0;
}