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#include <bits/stdc++.h>
using namespace std;
#define f first
#define s second
#define int long long
int32_t main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    int n,m,sc;
    cin >> n >> m >> sc;
    vector<pair<pair<int,int>,bool>> v;
    for(int i=0;i<m;i++){
        int a,b;
        cin >> a >> b;
        v.push_back({{a,b},1});
    }
    sort(v.begin(),v.end());
    for(int i=1;i<m;i++){
        if(v[i-1].f.s+1 == v[i].f.f){
            v[i].f.f = v[i-1].f.f;
            v[i-1].s=0;
        }
    }
    for (auto i : v){
        if(i.s){
            if(i.f.f <= sc and sc <= i.f.s){
                int a=i.f.f-1;
                int b=i.f.s+1;
                if(a<=0) {cout << b; return 0;}
                if(b>n) {cout << a; return 0;}
                int oa=abs(a-sc); int ob=abs(b-sc);
                if(oa==ob) cout << a;
                else if(oa<ob) cout << a;
                else cout << b;

                return 0;
            }
        }
    }
}