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#include <bits/stdc++.h>
using namespace std;
#define endl '\n'
using LL=long long;
using LD=long double;
#define FOR(i,l,r) for(auto i=(l);i<=(r);++i)
#define ROF(i,l,r) for(auto i=(l);i>=(r);--i)
#define REP(i,n) FOR(i,0,(n)-1)
#define ITF(e,c) for(auto&e:(c))
#define ssize(x) int(x.size())
#ifdef DEBUG
auto operator<<(auto&o,auto p)->decltype(p.first,o){return o<<'('<<p.first<<", "<<p.second<<')';}
auto operator<<(auto&o,auto&x)->decltype(x.end(),o){o<<'{';int i=0;for(auto e:x)o<<(", ")+2*!i++<<e;return o<<'}';}
#define debug(x...) cerr<<"["#x"]: ",[](auto...$){((cerr<<$<<"; "),...);}(x),cerr<<'\n'
#else
#define debug(...) {}
#endif

LL N,S;
int M;
set<pair<LL,bool>> rgs;

int main() {
  cin.tie(0)->sync_with_stdio(0);

  /// input
  {
    cin>>N>>M>>S;
    LL l,r;
    REP(i,M) {
      cin>>l>>r;
      if (rgs.count({l-1,1})) rgs.erase({l-1,1});
      else rgs.insert({l,0});
      if (rgs.count({r+1,0})) rgs.erase({r+1,0});
      else rgs.insert({r,1});
    }
    debug(rgs);
  }
  
  /// output
  {
    debug(S);
    auto it = ranges::lower_bound(rgs, pair{S,true});
    if (it->first == N) cout << prev(it)->first-1;
    else if (prev(it)->first == 1) cout << it->first+1;
    else {
      if (abs(S-(it->first+1)) < abs(S-(prev(it)->first-1))) cout << it->first+1 << endl;
      else cout << prev(it)->first-1 << endl;
    }
  }

  return 0;
}