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#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;
typedef vector<int> vi;
typedef pair<int, int> pii;

#define FOR(x, b, e) for(int x = (b); x <= (e); ++(x))
#define FORD(x, b, e) for(int x = (b); x >= (e); --(x))
#define REP(x, n) for(int x = 0; x < (n); ++x)
#define ALL(c) (c).begin(), (c).end()
#define SIZE(x) ((int)(x).size())
#define FOREACH(a, b) for (auto&a : (b))
#define PB push_back
#define PF push_front
#define ST first
#define ND second
#define DBG(vari) cerr<<#vari<<" = "<<(vari)<<endl

template <typename T>
std::ostream& operator<<(std::ostream &output, const vector<T> &vec)
{
    output << "[";
    FOREACH(x, vec) output << x << ", ";
    output << "]";
    return output;
}

template <typename T, typename U>
std::ostream& operator<<(std::ostream &output, const pair<T,U> &p)
{
    output << "(";
    output << p.ST << ", " << p.ND;
    output << ")";
    return output;
}


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

  ll n; cin >> n;
  int m; cin >> m;
  ll s; cin >> s;

  vector<pair<ll,ll>> LR(m);  
  REP(i, m) {
    cin >> LR[i].ST >> LR[i].ND;
  }

  sort(ALL(LR)); 

  ll najl = -1;

  REP(i, SIZE(LR)) {
    ll cand = LR[i].ST-1;
    if (cand >= 1 && ((i == 0 || LR[i-1].ND < cand) && cand < s))
      najl = cand;
  }

  ll najl2 = -1;
  REP(i, SIZE(LR)) {
    ll cand = LR[i].ND+1;
    if (cand <= n && ((i == SIZE(LR)-1 || LR[i+1].ST > cand) && cand > s)) {
      najl2 = cand;
      break;
    }
  }

  if (najl == -1) {
    cout << najl2;
  }
  else if (najl2 == -1) {
    cout << najl;
  }
  else
  {
    if (s - najl < najl2 - s)
      cout << najl;
    else if (s - najl > najl2 - s)
      cout << najl2;
    else
      cout << najl;
  }
  cout << endl;
}