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#include <iostream>
#include <vector>
#include <utility>
#include <algorithm>

using namespace std;

void input(long long & n, long long & m, long long & s, vector<pair<long long, long long>> & intervals) {
    cin >> n >> m >> s;
    intervals.resize(m+2);
    for(int i = 0; i < m; i++) {
        cin >> intervals[i].first >> intervals[i].second;
    }
    intervals[m] = {0, 0};
    intervals[m+1] = {n+1, n+1};
    sort(intervals.begin(), intervals.end());
}

void solve() {
    long long n, m, s;
    vector<pair<long long, long long>> intervals;
    input(n, m, s, intervals);

    long long sinv = -1;
    for(int i = 0; i < intervals.size(); i++) {
        if(intervals[i].first <= s && intervals[i].second >= s) {
            sinv = i;
            break;
        }
    }

    long long left = 0;
    for(int i = sinv; i > 0; i--) {
        if(intervals[i].first - 1 > intervals[i-1].second) {
            left = intervals[i].first - 1;
            break;
        }
    }
    long long right = 0;
    for(int i = sinv; i < intervals.size() - 1; i++) {
        if(intervals[i].second + 1 < intervals[i+1].first) {
            right = intervals[i].second + 1;
            break;
        }
    }
    
    long long result = 0;
    if (left == 0) {
        result = right;
    } else if (right == 0) {
        result = left;
    } else if ((right - s) < (s - left)) {
        result = right;
    } else {
        result = left;
    }

    cout << result << "\n";
}

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

    solve();

    return 0;
}