#include <bits/stdc++.h>
using namespace std;
bool data[100001][100];
int main() {
  int n;
  cin >> n;
  for (int i = 1; i <= n; i++) {
    int r, l;
    cin >> r >> l;
    for (int j = r; j <= l; j++) data[i][j] = true;
  }
  vector<int> v;
  for (int i = 1; i <= n; i++) {
    int ok = 0;
    for (int j = 1; j <= n; j++) {
      if (data[j][i]) ok++;
    }
    if (ok + 1 >= i) v.push_back(i);
  }
  if (v.size()) {
    sort(v.begin(), v.end());
    cout << v[v.size() - 1] - 1 << endl;
  } else
    cout << 0 << endl;
  return 0;
}
