#include <bits/stdc++.h>   using namespace std;   int main() {     int *xi, *di, n;     cin >> n;     xi = new int[n];     di = new int[n];     for (int i = 0; i < n; i++) cin >> xi[i] >> di[i];     for (int i = 0; i < n; i++) {       for (int j = 0; j < n; j++) {         if (xi[i] + di[i] == xi[j] && xi[j] + di[j] == xi[i] && j != i) {           cout <<  YES ;           return 0;         }       }     }     cout <<  NO ;     return 0;   }   