1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
#include <bits/stdc++.h>
#define ll long long
#define range(i, n) for (int i = 0; i < n; i++)

using namespace std;

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

    ll n, s;
    int m;
    cin >> n >> m >> s;
    vector<pair<ll, ll>> in(m);
    range(i, m) cin >> in[i].first >> in[i].second;
    sort(in.begin(), in.end());
    vector<pair<ll, ll>> v;
    for (int i = 1; i < m; i++) {
        if (in[i-1].second + 1 == in[i].first) in[i].first = in[i-1].first;
        else v.push_back(in[i-1]);
    }
    v.push_back(in[m-1]);
    for (int index = 0; index < v.size(); index++) {
        if (s > v[index].second) continue;
        if (s < v[index].first) {
            cout << s << "\n";
            return 0;
        }
        ll top = v[index].second + 1;
        ll bot = v[index].first - 1;
        if (bot == 0) {
            cout << top << "\n";
            return 0;
        }
        if (top == n+1) {
            cout << bot << "\n";
            return 0;
        }
        if (s - bot <= top - s) {
            cout << bot << "\n";
        } else {
            cout << top << "\n";
        }
        return 0;
    }
}