#include <iostream>
#include <set>
#include <ranges>

int main() {
    std::cin.tie(nullptr) -> sync_with_stdio(false);
    int n;
    std::cin >> n;
    std::set<std::pair<int, int>> s;
    for([[maybe_unused]] const auto _: std::views::iota(0, n)) {
        int a, b;
        std::cin >> a >> b;
        if(s.contains(std::make_pair(a, b))) {
            std::cout << "Yes\n";
            std::exit(0);
        }
        s.emplace(a, b);
    }
    std::cout << "No\n";
}