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#include <bits/stdc++.h>
using namespace std;

typedef int64_t ll;
typedef uint64_t ull;
typedef unsigned int ui;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<long long> vll;
constexpr ll LINF = 1e18;
constexpr int INF = 1e9;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    ll n, m, s;
    cin >> n >> m >> s;

    vector<pair<ll, ll>> segments(m + 2);

    for (int i = 0; i < m; ++i) {
        cin >> segments[i].first >> segments[i].second;
    }
    segments[m] = {0, 0};
    segments[m + 1] = {n + 1, n + 1};
    sort(segments.begin(), segments.end());

    ll result = LINF;
    for (int i = 0; i < m + 1; ++i) {
        if (segments[i].second == segments[i + 1].first - 1) {
            continue;
        }

        if (abs(segments[i].second + 1 - s) < abs(result - s)) {
            result = segments[i].second + 1;
        }

        if (abs(segments[i + 1].first - 1 - s) < abs(result - s)) {
            result = segments[i + 1].first - 1;
        }
    }

    cout << result << endl;

    return 0;
}