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#include <unistd.h>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <utility>
#include <deque>
#include <iostream>
#include <algorithm>
#include <limits>

// using namespace std;
#define REP(i,n) for(int _n=(n), i=0;i<_n;++i)
#define FOR(i,a,b) for(int i=(a),_b=(b);i<=_b;++i)
#define FORD(i,a,b) for(int i=(a),_b=(b);i>=_b;--i)
#define TRACE(x) cerr << "TRACE(" #x ")" << endl;
#define DEBUG(x) cerr << #x << " = " << (x) << endl;
typedef long long LL;
typedef unsigned long long ULL;
using VINT = std::vector<int>;
using VLL = std::vector<LL>;
using VULL = std::vector<ULL>;

struct Range {
  long from = 0;
  long to = 0;
};

int main() {
  std::ios_base::sync_with_stdio(false);
  long n, m, s;
  std::cin >> n >> m >> s;
  std::map<long, Range> ranges;
  
  long from, to;
  REP(i, m) {
    std::cin >> from >> to;
    ranges.insert({from, {from, to}});
  }

  Range currentRange;
  std::vector<Range> sqashedRanges;
  for(auto it = ranges.begin(); it != ranges.end(); it++) {
    if (currentRange.from == 0) {
      currentRange = it->second;
      continue;
    }

    // if (currentRange.to + 1 == s) {
    //   currentRange = Range{currentRange.from, currentRange.to + 1};
    // }

    if (currentRange.to + 1 == it->second.from) {
      currentRange = Range{currentRange.from, it->second.to};
      continue;
    }

    sqashedRanges.push_back(currentRange);
    currentRange = it->second;
  }

  if (currentRange.from > 0) {
    sqashedRanges.push_back(currentRange);
  }

  long min = std::numeric_limits<long>::max();
  long currentMinLocation = 0;
  for (auto& range : sqashedRanges) {
    auto beforFrom = range.from -1;
    if (beforFrom > 0) {
      auto beforFromDistance = std::abs(beforFrom - s);
      if (min > beforFromDistance) {
        min = beforFromDistance;
        currentMinLocation = beforFrom;
      }
    }
    auto afterTo = range.to + 1;
    if (afterTo <= n) {
      auto afterToDistance = std::abs(afterTo - s);
      if (min > afterToDistance) {
        min = afterToDistance;
        currentMinLocation = afterTo;
      }
    }
  }

  std::cout << currentMinLocation << std::endl;
  
  return 0;
}