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

#define FOR(i, b) for (int i = 0; i < b; ++i)
#define sz(s) (int)s.size()
#define all(s) s.begin(), s.end()
#define mp make_pair
#define pb push_back
#define f first
#define s second

void solve()
{
    long long n, m, s;
    cin >> n >> m >> s;
    long long best = -1;

    vector<pair<long long, long long>> adj(m);

    FOR (i, m)
    {
        cin >> adj[i].first >> adj[i].second;
    }

    auto closer = [&](long long a, long long b)
    {
        if (a <= 0 or a == n + 1)
        {
            return b;
        }
        if (b <= 0 or b == n + 1)
        {
            return a;
        }

        if (abs(a - s) < abs(b - s))
        {
            return a;
        }
        else if (abs(a - s) > abs(b - s))
        {
            return b;
        }
        return min(a, b);
    };

    for (const auto& [st, kon] : adj)
    {
        vector<long long> to_check = {st - 1, kon + 1};
        for (const auto& x : to_check)
        {
            bool valid = true;
            for (const auto& [st2, kon2] : adj)
            {
                if (x >= st2 && x <= kon2)
                {
                    valid = false;
                    break;
                }
            }
            if (valid)
            {
                best = closer(best, x);
            }
        }
    }
    cout << best << '\n';
}

int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);

    solve();
}