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

struct Building
{
    long long start;
    long long end;
    bool operator<(const Building &other)
    {
        return this->end < other.end;
    }
};

int main()
{
    std::vector<Building> blocks;
    long long n,m,s;
    std::cin >> n >> m >> s;
    blocks.reserve(m);
    for (long long i=0;i<m;i++){
        long long l,r;
        std::cin >> l >> r;
        blocks.push_back({l, r});
    }

    std::sort(blocks.begin(), blocks.end());
    std::vector<Building> blocks2;
    blocks2.push_back(blocks.front());
    for (int i=1;i<blocks.size();i++)
    {
        if (blocks[i].start == blocks2[blocks2.size()-1].end+1){
            blocks2[blocks2.size()-1].end = blocks[i].end;
        }
        else {
            blocks2.push_back(blocks[i]);
        }
    }

    auto schoolBlock = std::lower_bound(blocks2.begin(), blocks2.end(), Building{s,s});
    if (schoolBlock->start == 1){
        std::cout << schoolBlock->end + 1 << std::endl;
        return 0;
    }
    if (schoolBlock->end == n){
        std::cout << schoolBlock->start-1 << std::endl;
        return 0;
    }

    long long fromLeft = s - (schoolBlock->start-1);
    long long fromRight = (schoolBlock->end + 1) - s;
    if (fromLeft == fromRight)
    {
        std::cout << schoolBlock->start-1 << std::endl;
    }
    else if (fromLeft < fromRight)
    {
        std::cout << schoolBlock->start-1 << std::endl;
    }
    else
    {
        std::cout << schoolBlock->end + 1 << std::endl;
    }
    return 0;
}