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#include "bits/stdc++.h"
#define int long long
#define pi pair<long long, long long>

#define meow main

using namespace std;

signed meow() {
  cin.tie((ostream *)!ios::sync_with_stdio(false));
  int n, m, s;
  cin >> n >> m >> s;
  vector<pi> taken(m);
  for (auto &[l, r] : taken)
    cin >> l >> r;

  sort(taken.begin(), taken.end());

  int best_l = LLONG_MIN;
  int mid;
  for (mid = 0; mid < m; mid++) {
    if (taken[mid].first <= s && s <= taken[mid].second)
      break;
  }

  int res_l = LLONG_MIN;
  for (int i = mid; i >= 0; i--) {
    if ((i == 0 || taken[i].first - 1 != taken[i - 1].second) &&
        taken[i].first - 1 > 0) {
      res_l = taken[i].first - 1;
      break;
    }
  }

  int res_r = LLONG_MIN;
  for (int i = mid; i < m; i++) {
    if ((i == m - 1 || taken[i].second + 1 != taken[i + 1].first) &&
        taken[i].second + 1 <= n) {
      res_r = taken[i].second + 1;
      break;
    }
  }

  if (res_r == LLONG_MIN) {
    cout << res_l << '\n';
    return 0;
  }

  if (res_l == LLONG_MIN) {
    cout << res_r << '\n';
    return 0;
  }

  if (s - res_l <= res_r - s) {
    cout << res_l << '\n';
  } else
    cout << res_r << '\n';
}