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
#include <bits/stdc++.h>
using namespace std;
#define st first
#define nd second
#define fast ios::sync_with_stdio(false); cin.tie(0); cout.tie(0)
#define int long long
void solve() {
    int n,m,s;
    cin>>n>>m>>s;
    vector<pair<int,int>>before;
    vector<pair<int,int>>after;
    for(int i =0;i<m;i++){
        int a,b;
        cin>>a>>b;
        if(a<=s && s<=b){
            before.push_back({a,s});
            after.push_back({s,b});
            continue;
        }
        if(a<=s){
            before.push_back({a,b});
            continue;
        }
        after.push_back({a,b});
    }
    if(before.size()==1 && before[0].st==s && s!=1){cout<<s-1<<'\n';return;}
    if(after.size()==1 && after[0].nd==s && s!=n){cout<<s+1<<'\n';return;}
    sort(before.begin(),before.end(),greater<>());
    sort(after.begin(),after.end());
    int best_before = -1;
    int last=s;
    for(auto [a,b]:before){
        if(b<last-1){best_before=last-1;break;}
        last=a;
    }
    best_before=max(best_before,last-1);
    int best = n+1;
    last=s;
    for(auto [a,b]:after){
        if(a>last+1){best=last+1;break;}
        last=b;
    }
    best=min(best,last+1);
    if(best_before>0 && (s-best_before<=best-s || best>n)){cout<<best_before<<'\n';return;}
    cout<<best<<'\n';
}
 
int32_t main() {
    //fast;
    //int z;
    //cin>>z;
    //while (z--) {
        solve();
    //}
}