#include <bits/stdc++.h>
using namespace std;
using LL = long long;
using pss = pair<string, string>;
using pis = pair<int, string>;
const int maxn = 300300;
int n;
LL val[maxn], mask[maxn], sum;
signed main() {
  while (cin >> n) {
    sum = 0;
    for (int i = 1; i <= n; i++) {
      cin >> val[i] >> mask[i];
      sum += val[i];
    }
    for (int i = 1; i <= n; i++) {
      if (sum < 0) {
        val[i] = -val[i];
      }
    }
    LL ret = 0;
    for (int k = 0; k < 62; k++) {
      LL tot = 0;
      for (int i = 1; i <= n; i++) {
        if (mask[i] == (1LL << k)) {
          tot += val[i];
        }
      }
      if (tot > 0) ret |= (1LL << k);
      for (int i = 1; i <= n; i++) {
        if ((1LL << k) & mask[i]) {
          mask[i] ^= (1LL << k);
          if (tot > 0) {
            val[i] = -val[i];
          }
        }
      }
    }
    cout << ret << endl;
  }
  return 0;
}
