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#include <bits/stdc++.h>
#define f first
#define s second
using namespace std;

int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);
	long long n, m, sz;
	cin >> n >> m >> sz;
	pair<long long, long long> lr[m];
	for(int i = 0; i < m; i++){
		cin >> lr[i].f >> lr[i].s;
	}
	sort(lr, lr+m);
	vector<pair<long long, long long>> v;
	pair<long long, long long> p = lr[0];
	for(int i = 1; i < m; i++){
		if(p.s + 1 == lr[i].f) p.s = lr[i].s;
		else{
			v.push_back(p);
			p = lr[i];
		}
	}
	v.push_back(p);
	for(auto& i : v){
		if(i.f > sz || i.s < sz) continue;
		if(i.f == 1){
			cout << i.s + 1;
			return 0;
		}
		if(i.s == n){
			cout << i.f - 1;
			return 0;
		}
		if(sz - i.f <= i.s - sz){
			cout << i.f - 1;
			return 0;
		}else{
			cout << i.s + 1;
			return 0;
		}
	}
	return 0;
}