#include <bits/stdc++.h>
using namespace std;

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    long long n, s;
    int m;
    cin >> n >> m >> s;

    unordered_map<long long, long long> left, right;

    for(int i = 0; i < m; i++) {
        long long l, r;
        cin >> l >> r;
        left[r] = l - 1;
        right[l] = r + 1;

        if(l <= s && s <= r) {
            left[s] = l - 1;
            right[s] = r + 1;
        }
    }

    long long L, R;
    L = R = s;

    while(left.find(L) != left.end()) {
        L = left[L];
    }
    while(right.find(R) != right.end()) {
        R = right[R];
    }

    if(L == 0) {
        cout << R;
        return 0;
    }
    if(R == n + 1) {
        cout << L;
        return 0;
    }
    if(s - L <= R - s) {
        cout << L;
        return 0;
    }
    cout << R;

    return 0;
}