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
48
49
50
51
52
53
54
55
56
57
58
#include <bits/stdc++.h>
using namespace std;
#define rep(a, b) for (int a = 0; a < (b); a++)
#define rep1(a, b) for (int a = 1; a <= (b); a++)
#define all(x) (x).begin(), (x).end()
using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
const int MOD = 1e9 + 7;

#define LOCAL false

ll n, s;
int m;

vector<pll> ivls1;

int main() {
    ios_base::sync_with_stdio(0); cin.tie(0);
    if (LOCAL) {
        ignore=freopen("io/in", "r", stdin);
        ignore=freopen("io/out", "w", stdout);
    }

    cin >> n >> m >> s;

    ll l, r;
    rep(i, m) {
        cin >> l >> r;
        ivls1.push_back({l, r});
    }
    sort(all(ivls1));

    vector<pll> ivls;
    for (auto [l, r]: ivls1) {
        if (ivls.empty()) {
            ivls.push_back({l, r});
            continue;
        }
        auto [l2, r2] = ivls.back();
        if (r2+1 == l) {
            ivls.pop_back();
            ivls.push_back({l2, r});
        } else ivls.push_back({l, r});
    }

    for (auto [l, r]: ivls) {
        if (l <= s && s <= r) {
            if (r == n) cout << l-1 << "\n";
            else if (l == 1) cout << r+1 << "\n";
            else if (s-(l-1) <= (r+1)-s) cout << l-1 << "\n";
            else cout << r+1 << "\n";
            return 0;
        }
    }

    return 0;
}