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#include <iostream>
#include <vector>
#include <algorithm>
#include <cassert>

using ll = long long;
#define debug(x) #x << " = " << x << '\n'

int main() {
  #ifdef LOCAL
    freopen("input.txt", "r", stdin);
  #endif
  std::ios_base::sync_with_stdio(false);
  std::cin.tie(0);
  
  ll n, s;
  int m;
  std::cin >> n >> m >> s;

  std::vector<std::pair<ll, ll>> a(m);
  for (auto &[l, r] : a) {
    std::cin >> l >> r;
  }

  std::sort(a.begin(), a.end());

  std::vector<std::pair<ll, ll>> free;

  free.push_back({1, a[0].first - 1});
  for (int i = 0; i + 1 < m; i++) {
    free.push_back({a[i].second + 1, a[i + 1].first - 1});
  }
  free.push_back({a[m - 1].second + 1, n});

  std::sort(free.begin(), free.end());

  ll where = -1;
  ll minDist = n + 1;

  auto chmin = [&](ll p) {
    if (std::abs(s - p) < minDist) {
      minDist = std::abs(s - p);
      where = p;
    } else if (std::abs(s - p) == minDist) {
      if (p < where) {
        where = p;
      }
    }
  };

  for (const auto &[l, r] : free) {
    if (l <= r) {
      chmin(l);
      chmin(r);
      if (l <= s && s <= r) {
        chmin(s);
      }
    }
  }

  std::cout << where;
  
  return 0;
}