#include <iostream>
#include <vector>
#include <set>
#include <utility>
#include <algorithm>
#include <cstdint>
using namespace std;

#define int int64_t

int32_t main() {
    int n, m, s;
    cin >> n >> m >> s;
    vector<pair<int, int>> in(m);
    for(int i = 0; i < m; i++) {
        cin >> in[i].first >> in[i].second;
    }
    sort(in.begin(), in.end());

    vector<pair<int, int>> a;
    for(auto [l, r] : in) {
        if(!a.empty() && a.back().second + 1 == l) {
            int L = a.back().first;
            a.pop_back();
            a.push_back({L, r});
        } else {
            a.push_back({l, r});
        }
    }
    
    int left = -1, right = -1;
    for(auto [l, r] : a) {
        if(s >= l && s <= r) {
            left = l - 1;
            right = r + 1;
        }
    }

    int op1 = abs(s - right) + 1, op2 = abs(s - left) + 1;
    if(left < 1 && right <= n) {
        cout << right;
    } else if(left >= 1 && right > n){
        cout << left;
    } else {
        if(op1 < op2) {
            cout << right;
        } else {
            cout << left;
        }
    }

    return 0;
}