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#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<ll,ll> ll_pair;

vector <ll_pair> seg;

void read(int m){
    ll x, y;
    for(int i = 0; i < m; i++){
        cin >> x >> y;
        seg.push_back({x, y});
    }
    return;
}

vector <ll> v;

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    ll n, m, s;
    cin >> n >> m >> s;
    read(m);
    sort(seg.begin(), seg.end());
    ll ans = 1;
    for(int i = 0; i < seg.size(); i++){
        if(ans <= s){
            if(seg[i].first <= ans && seg[i].second >= ans) ans = seg[i].second + 1;
            else{
                v.push_back(ans);
                if(i == 0 || (i != 0 && seg[i].first - 1 != seg[i - 1].second)){
                    ans = seg[i].first - 1;
                }
                else ans = seg[i].second + 1;
            }
            if(i + 1 == seg.size() && ans < n) v.push_back(ans);
        }
        else break;
    }
    ans = n;
    for(int i = seg.size() - 1; i >= 0; i--){
        if(ans >= s){
            if(seg[i].first <= ans && seg[i].second >= ans) ans = seg[i].first - 1;
            else{
                v.push_back(ans);
                if(i == seg.size() - 1 || (i != seg.size() - 1 && seg[i].second + 1 != seg[i + 1].first)){
                    ans = seg[i].second + 1;
                }
                else ans = seg[i].first - 1;
            }
            if(i == 0 && ans > 0) v.push_back(ans);
        }
        else break;
    }
    sort(v.begin(), v.end(), [&](const ll& a, const ll& b){
        if(abs(s - a) == abs(s - b)){
            return a < b;
        }
        return abs(s - a) < abs(s - b);
    });
    cout << v[0] << "\n";
    return 0;
}