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#include <algorithm>
#include <iostream>
#include <list>
#include <vector>

using namespace std;

class Node {
public:
    long long start, end;

    bool operator<(const Node &other) const {
        return start < other.start;
    }
};

vector<Node> v;
list<Node*> lst;

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

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

    for (int i = 0; i < m; ++i) {
        long long start, end;
        cin >> start >> end;
        v.push_back(Node(start, end));
    }

    sort(v.begin(), v.end());

    for (Node &node: v) {
        lst.push_back(&node);
    }

    auto it = lst.begin();
    while(it != lst.end()) {
        long long start1 = (*it)->start;
        long long end1 = (*it)->end;
        it++;
        if(it == lst.end()) {
            break;
        }
        long long start2 = (*it)->start;
        if(start2 == end1 + 1) {
            (*it)->start = start1;
            it--;
            it = lst.erase(it);
        }
    }

    long long best = 2000000000000;
    long long res;
    for (auto it = lst.begin(); it != lst.end(); ++it) {
        long long start = (*it)->start;
        long long end = (*it)->end;
        if(s >= start && s <= end) {
            if(start > 1) {
                best = s - start + 1;
                res = start-1;
            }
            if(end < n && end - s + 1 < best) {
                best = end - s + 1;
                res=end+1;
            }
            break;
        }
    }

    cout << res << '\n';

    return 0;
}