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#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
#define ll long long
#define pll pair<ll, ll>
#define pb push_back
vector<pll>v;
ll odl(ll a, ll b) {
    if (a < b) swap(a, b);
    return a - b;
}
void f() {
    //input
    ll n, m, x, ans = 1e18; cin >> n >> m >> x;
    for (int i = 0; i < m; i++) {
        ll l, r; cin >> l >> r;
        v.pb({ l, r });
    }
    sort(v.begin(), v.end());
    v.pb({ n + 1, n + 1 });
    ll curr = 0;
    for (pll i : v) {
        if (x > curr && x < i.first) ans = x;
        if (curr + 1 >= i.first) {
            curr = i.second;
            continue;
        }
        if (odl(x, curr + 1) < odl(x, ans)) ans = curr + 1;
        if (odl(x, i.first - 1) < odl(x, ans)) ans = i.first - 1;
        curr = i.second;
    }
    cout << ans;
}
int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    f();
}