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// PA 2024 2C - Szkola
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
using namespace std;

struct Edge {
	long long a;
	long long b;
	
	Edge(long long a, long long b) {
		this->a = a;
		this->b = b;
	}
	
	bool operator<(const Edge& X) const {
		return this->a < X.a;
	}
};

int main()
{
	ios_base::sync_with_stdio(0);
	long long n, m, s, a, b, res, cand1, cand2;
	vector<Edge> occup;
	vector<Edge> occupComp;
	
	cin >> n;
	cin >> m;
	cin >> s;
	
	for (long long i = 0; i < m; ++i) {
		cin >> a;
		cin >> b;
		occup.push_back(Edge(a, b));
	}
	
	sort(occup.begin(), occup.end());
	
	for (unsigned long long i = 0; i < occup.size(); ++i) {
		if (i == 0 || occup[i - 1].b + 1 < occup[i].a) {
			occupComp.push_back(occup[i]);
		} else {
			occupComp[occupComp.size() - 1].b = occup[i].b;
		}
	}
		
	for (unsigned long long i = 0; i < occupComp.size(); ++i) {		
		if (occupComp[i].a <= s && s <= occupComp[i].b) {
			if (occupComp[i].a == 1) {
				cand1 = n;
			} else {
				cand1 = s - occupComp[i].a + 1;
			}
			
			if (occupComp[i].b == n) {
				cand2 = n;
			} else {
				cand2 = occupComp[i].b - s + 1;
			}
			if (cand1 <= cand2) {
				res = occupComp[i].a - 1;
			} else {
				res = occupComp[i].b + 1;
			}
		}		
	}
	
	cout << res;
	
	return 0;
}