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#include <iostream>
#include <vector>
#include <algorithm>
#include <climits>

using namespace std;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    
    long long n, m, s;
    cin >> n >> m >> s;
    
    vector<pair<long long, long long>> intervals(m);
    for (int i = 0; i < m; i++) {
        cin >> intervals[i].first >> intervals[i].second;
    }
    
    // Sort intervals
    sort(intervals.begin(), intervals.end());
    
    long long closest_left = -1;
    long long closest_right = -1;
    
    // Find the interval containing s or the closest intervals around s
    int idx = -1;
    for (int i = 0; i < m; i++) {
        if (intervals[i].first <= s && s <= intervals[i].second) {
            idx = i;
            break;
        }
        
        if (intervals[i].first > s) {
            // s is between intervals[i-1] and intervals[i]
            closest_right = intervals[i].first - 1;
            if (i > 0) {
                closest_left = intervals[i-1].second + 1;
            } else {
                closest_left = 1; // No interval before, so first building is free
            }
            break;
        }
    }
    
    if (idx != -1) {
        // s is in intervals[idx]
        // Check for free buildings to the left
        if (idx > 0) {
            closest_left = intervals[idx].first - 1;
            if (closest_left < intervals[idx-1].second + 1) {
                closest_left = intervals[idx-1].second + 1;
            }
        } else if (intervals[idx].first > 1) {
            closest_left = intervals[idx].first - 1;
        }
        
        // Check for free buildings to the right
        if (idx < m-1) {
            closest_right = intervals[idx].second + 1;
            if (closest_right > intervals[idx+1].first - 1) {
                closest_right = intervals[idx+1].first - 1;
            }
        } else if (intervals[idx].second < n) {
            closest_right = intervals[idx].second + 1;
        }
    } else if (intervals[m-1].second < s) {
        // s is after all intervals
        closest_left = intervals[m-1].second + 1;
    }
    
    // Ensure buildings are in valid range
    if (closest_left < 1 || closest_left > n) closest_left = -1;
    if (closest_right < 1 || closest_right > n) closest_right = -1;
    
    // Calculate distances
    long long left_dist = (closest_left != -1) ? abs(s - closest_left) : LLONG_MAX;
    long long right_dist = (closest_right != -1) ? abs(s - closest_right) : LLONG_MAX;
    
    if (left_dist < right_dist) {
        cout << closest_left << endl;
    } else if (right_dist < left_dist) {
        cout << closest_right << endl;
    } else if (closest_left != -1 && closest_right != -1) {
        cout << min(closest_left, closest_right) << endl;
    } else if (closest_left != -1) {
        cout << closest_left << endl;
    } else {
        cout << closest_right << endl;
    }
    
    return 0;
}