20 20
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
 10 4
0 1 4 2 7 0 10 0 5 8
 10 7
10 8 6 5 0 0 0 4 3 9
 10 1
8 7 0 2 0 10 0 0 3 5
 10 7
7 9 2 10 0 0 0 3 5 1
 10 2
10 0 9 0 0 4 2 6 8 0
 10 2
0 7 0 10 8 0 4 2 3 0

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
 3
4
8
9
 1
5
6
10
 2
4
5
7
8
10
 1
2
6
7
 1
2
3
4
6
7
8
9
 4
5
6
7
8

#include <bits/stdc++.h>
using namespace std;
int p[100], d[100];
int main() {
  int n, pos = 0;
  for (cin >> n; pos < n; ++pos) cin >> p[pos] >> d[pos];
  bool ok = false;
  for (int i = 0; i < n; ++i)
    for (int j = i + 1; j < n; ++j)
      if (p[i] + d[i] == p[j] && p[i] == d[j] + p[j]) ok = true;
  if (ok)
    cout << "YES\n";
  else
    cout << "NO\n";
}
