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#include <bits/stdc++.h>

using namespace std;

#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) {}
#endif

#define x first
#define y second
#define ire(x, a, b) ((a) <= (x) && (x) < (b))
#define vec vector
#define rep(i, a, b) for (int i = a; i < (b); ++i)
#define all(x) (x).begin(), (x).end()

using ll = long long;
using pll = pair<ll, ll>;

int main() {
    cin.tie(0)->sync_with_stdio(0);
    ll W, N, s;
    cin >> W >> N >> s;
    vec<pll> ints(N);
    --s;
    rep (n, 0, N) {
        cin >> ints[n].x >> ints[n].y;
        ints[n].x--;
    }
    ll best = 1e18;
    auto t = [&](ll x) {
        debug(x);
        if (abs(s - x) == abs(s - best)) {
            if (x < best) {
                best = x;
            }
        }
        if (abs(s - x) < abs(s - best)) {
            best = x;
        }
    };

    sort(all(ints));
    rep (n, 0, N) {
        if ((n == 0 && ints[n].x > 0) || (n > 0 && ints[n-1].y != ints[n].x)) {
            t(ints[n].x-1);
        }
        if ((n == N-1 && ints[n].y < W) || (n < N-1 && ints[n+1].x != ints[n].y)) {
            t(ints[n].y);
        }
    }
    cout << best+1 << "\n";
    return 0;
}