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#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

#define int long long
#define pii pair<int, int>
#define fi first
#define se second

const int INF = 1e15 + 7;


void solve(){
	
	int n, m, s;
	cin >> n >> m >> s;
	map<int, int> used;
	vector<int> pos;
	
	for(int i = 1; i <= m; i++){
		
		int l, r;
		cin >> l >> r;
		
		used[l] = used[r] = 1;
		pos.push_back(l - 1);
		pos.push_back(r + 1);
	}
	
	int ans = INF, ind = 1e12 + 1;
	
	for(auto u : pos){
		
		if(used[u] || u < 1 || u > n) continue;
		
		if(abs(u - s) < ans){
			
			ans = abs(u - s);
			ind = u;
		}
		
		else if(abs(u - s) == ans){
			
			ind = min(ind, u);
		}
	}
	
	cout << ind << '\n';
}

bool multi = 0;

signed main(){
	
	ios_base::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);
	
	int t = 1;
	if(multi) cin >> t;
	while(t--) solve();
	
	return 0;
}