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#include <bits/stdc++.h>

constexpr long long INF = 1e15;

long long n, s;
int m;
std::pair<long long, long long> buildings[1003];
long long school_idx;
long long res = INF;
long long home_idx;

void load_data();
void sort_buildings();
void find_school();
void find_best_location_left();
void find_best_location_right();
void print_result();

// OK
int main() {
    load_data();
    sort_buildings();
    find_school();
    find_best_location_left();
    find_best_location_right();
    print_result();
    return 0;
}

// OK
void load_data() {
    std::cin >> n >> m >> s;
    for (int i = 0; i < m; ++i) {
        std::cin >> buildings[i].first >> buildings[i].second;
    }
}

// OK
void sort_buildings() {
    std::sort(buildings, buildings + m);
}

// OK
void find_school() {
    for (int i = 0; i < m; ++i) {
        if (buildings[i].first <= s && s <= buildings[i].second) {
            school_idx = i;
            break;
        }
    }
}

void find_best_location_left() {
    for (int i = school_idx; i >= 1; --i) {
        bool space_between_buildings = buildings[i].first - buildings[i - 1].second > 1;
        if (space_between_buildings) {
            long long dist = s - buildings[i].first;
            if (dist < res) {
                res = dist;
                home_idx = buildings[i].first - 1;
            }
        }
    }

    if (buildings[0].first > 1) {
        long long dist = s - buildings[0].first;
        if (dist < res) {
            res = dist;
            home_idx = buildings[0].first - 1;
        }
    }
}

void find_best_location_right() {
    for (int i = school_idx; i < m - 1; ++i) {
        bool space_between_buildings = buildings[i + 1].first - buildings[i].second > 1;
        if (space_between_buildings) {
            long long dist = buildings[i].second - s;
            if (dist < res) {
                res = dist;
                home_idx = buildings[i].second + 1;
            }
        }
    }

    if (buildings[m - 1].second < n) {
        long long dist = buildings[m - 1].second - s;
        if (dist < res) {
            res = dist;
            home_idx = buildings[m - 1].second + 1;
        }
    }
}

// OK
void print_result() {
    std::cout << home_idx << std::endl;
}