#include <iostream>
#include <iomanip>//小数点出力用
//cout << fixed << setprecision(10) << ans;
#include <cmath>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <set>
#include <map>
using ll = long long;
using namespace std;
#define modP7 1'000'000'007
#define modP 998244353
bool chkrng0idx(int pos, int sup) { return (0 <= pos && pos < sup); }
int clk4(int num) { return (num - 2) * (num % 2); }
void yn(bool tf) { cout << (tf ? "Yes\n" : "No\n"); }


int main() {
    int N;
    cin >> N;
    set<pair<int, int>>S;
    for (int i = 0;i < N;i++) {
        int A, B;
        cin >> A >> B;
        S.insert({ A,B });
    }
    yn(S.size() != N);
    return 0;
}