#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n;
    cin >> n;
    array<array<bool,1000>,1000> B{};
    short x, y;
    while(n--){
        cin >> x >> y;
        x--, y--;
        if(B[x][y]){
            cout << "Yes\n";
            return 0;
        }
        B[x][y] = true;
    }
    cout << "No\n";
}