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#include "bits/stdc++.h"
using namespace std;

#define rep(i, b, e) for (int i = (b); i <= (e); i++)
#define per(i, b, e) for (int i = (e); i >= (b); i--)
#define FOR(i, b, e) rep(i, b, (e)-1)
#define SZ(x) int(x.size())
#define all(x) x.begin(), x.end()
#define pb push_back
#define mp make_pair
#define st first
#define nd second
using ll = long long;
using vi = vector<int>;
using pii = pair<int, int>;

auto& operator<<(auto& o, pair<auto, auto> p) {
  return o << "(" << p.st << ", " << p.nd << ")";
}
auto operator<<(auto& o, auto x) -> decltype(end(x), o) {
  o << "{";
  int i = 0;
  for (auto e : x)
    o << ", " + 2 * !i++ << e;
  return o << "}";
}
#ifdef LOCAL
#define deb(x...)                       \
  cerr << "[" #x "]: ", [](auto... $) { \
    ((cerr << $ << "; "), ...) << endl; \
  }(x)
#else
#define deb(...)
#endif

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie();

  ll n, m, s;
  cin >> n >> m >> s;

  vector<pair<ll, ll>> seg(m);

  for (int i = 0; i < m; i++) {
    ll a, b;
    cin >> a >> b;
    seg[i] = {a, b};
  }

  seg.push_back({0, 0});
  seg.push_back({n + 1, n + 1});
  sort(all(seg));

  ll nr = -1000000000000000000LL;
  for (int i = 1; i <= m; i++) {
    if (seg[i].first - 1 > seg[i - 1].second) {
      if (abs(s - nr) > abs(s - seg[i].first + 1)) {
        nr = seg[i].first - 1;
      }
    }
    if (seg[i].second + 1 < seg[i + 1].first) {
      if (abs(s - nr) > abs(s - seg[i].second - 1)) {
        nr = seg[i].second + 1;
      }
    }
  }

  cout << nr << "\n";
}