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#include<bits/stdc++.h>
 
#define pb push_back
#define pob pop_back
#define eb emplace_back
#define fi first
#define se second
#define turbo ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define mid ((l+r)/2)
#define midLL ((l+r)/2LL)
#define mide ((lo+hi)/2)
#define mideLL ((lo+hi)/2LL)
#define endl '\n'
#define random_shuffle shandom_ruffle
#define lowbit(x) x&(-x)
#define bits(x) __builtin_popcount(x) 
#define mins(se) (*se.begin())
#define maxs(se) (*--se.end())
#define all(x) x.begin(), x.end()
#define log2_floor(i) (i ? __builtin_clzll(1) - __builtin_clzll(i) : -1)
#define siz(cont) ((int)cont.size())
#define each(it, cont) for(auto &it : cont)

using ll = long long;
using pii = std::pair<int, int>;
using pll = std::pair<ll, ll>;
using pli = std::pair<ll, int>;
using pil = std::pair<int, ll>;
using vll = std::vector<pll>;
using vii = std::vector<pii>;
using vi = std::vector<int>;
using vl = std::vector<ll>;
using vvl = std::vector<vl>;
using vvi = std::vector<vi>;
using vvii = std::vector<vii>;
using vli = std::vector<pli>;
using vvli = std::vector<vli>;
using vil = std::vector<pil>;
using vvil = std::vector<vil>;
using vc = std::vector<char>;
using vvc = std::vector<std::vector<char>>;
using vb = std::vector<bool>;
using vvb = std::vector<vb>;

void err() { std::cout << "\n"; fflush(stdout); }
template<class T, class... Ts>
void err(T arg, Ts &... args) {
    std::cout << arg << ' ';
    err(args...);
}

using namespace std;

signed main() { 
    turbo;
    ll n, m, s; cin >> n >> m >> s;
    vll v(m+2);
    for (int i = 1; i <= m; i++)
        cin >> v[i].fi >> v[i].se;

    v[0] = {0, 0};
    v[m+1] = {n+1, n+1};

    ll res = -n;

    sort(all(v));

    for (int i = 1; i <= m; i++) {
        if (v[i].fi-1 != v[i-1].se)
            if (abs(s-(v[i].fi-1)) < abs(s-res))
                res = v[i].fi-1;
        if (v[i].se+1 != v[i+1].fi)
            if (abs(s-(v[i].se+1)) < abs(s-res))
                res = v[i].se+1;
    }

    cout << res;
}