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//Sylwia Sapkowska 
#include <bits/stdc++.h> 
#pragma GCC optimize("O3", "unroll-loops")
using namespace std;

#define int long long
typedef pair<int, int> T;
const int oo = 1e18;

void solve(){
    int n, m, s; cin >> n >> m >> s;
    T ans = {oo, oo};
    vector<T>a(m);
    for (auto &[l, r]: a) cin >> l >> r;
    sort(a.begin(), a.end());
    auto check = [&](int l, int r){
        if (l > r) return;
        assert(!(l <= s && s <= r));
        if (s < l) ans = min(ans, T{l-s, l});
        if (s > r) ans = min(ans, T{s-r, r});
    };
    check(1, a[0].first-1);
    check(a[m-1].second+1, n);
    for (int i = 1; i<m; i++){
        check(a[i-1].second+1, a[i].first-1);
    }
    cout << ans.second << "\n";
}
 
int32_t main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    solve();

    return 0;
}