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// Arti1990, II UWr

#include <bits/stdc++.h>

#define forr(i, n)                  for(int i=0; i<n; i++)
#define FOREACH(iter, coll)         for(auto iter = coll.begin(); iter != coll.end(); ++iter)
#define FOREACHR(iter, coll)        for(auto iter = coll.rbegin(); iter != coll.rend(); ++iter)
#define lbound(P,K,FUN)             ({auto SSS=P, PPP = P-1, KKK=(K)+1; while(PPP+1!=KKK) {SSS = (PPP+(KKK-PPP)/2); if(FUN(SSS)) KKK = SSS; else PPP = SSS;} PPP;})
#define testy()                     int _tests; cin>>_tests; FOR(_test, 1, _tests)
#define CLEAR(tab)                  memset(tab, 0, sizeof(tab))
#define CONTAIN(el, coll)           (coll.find(el) != coll.end())
#define FOR(i, a, b)                for(int i=a; i<=b; i++)
#define FORD(i, a, b)               for(int i=a; i>=b; i--)
#define MP                          make_pair
#define PB                          push_back
#define ff                          first
#define ss                          second
#define deb(X)                      X;
#define SIZE(coll) 					((int)coll.size())

#define M 1000000007
#define INF 1000000000000000007LL

using namespace std;

long long n, m, s, a, b;
vector <long long> v;

int solve()
{
    cin >> n >> m >> s;
    forr(i, m)
    {
        cin >> a >> b;
        v.PB(a);
        v.PB(b);
    }
    v.PB(0);
    v.PB(n+1);
    sort(v.begin(), v.end());

    pair <long long, long long> res = {INF, 0};
    for(int i=0; i < v.size(); i += 2)
    {
        auto p = v[i];
        auto k = v[i+1];
        if(p+1 < k)
        {
            res = min(res, {abs(p+1 - s), p+1});
            res = min(res, {abs(k-1 - s), k-1});
        }
    }

    cout << res.ss << '\n';

    return 0;
}

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

    solve();

    return 0;
}