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#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define f first
#define s second

vector <ll> v;
vector <ll> wej;

int main() {
    ll n, m, s;
    ll a, b;
    cin >> n >> m >> s;
    ll l = -1, r = n + 1;

    for(int i = 0; i < m; i++){
        cin >> a >> b;

        wej.push_back(a);
        wej.push_back(b);

        if(a != 1) v.push_back(a - 1);
        v.push_back(b + 1);
    }

    sort(v.begin(), v.end());
    sort(wej.begin(), wej.end());

    for(int i = 0; i < v.size(); i++){
        if(binary_search(wej.begin(), wej.end(), v[i])) continue;

        if(v[i] < s){
            l = v[i];
        }
        else if(v[i] > s){
            r = v[i];
            break;
        }
    }

    if(l == -1){
        cout << r;
        return 0;
    }
    else if(r == n + 1) {
        cout << l;
        return 0;
    }

    if(s - l <= r - s){
        cout << l;
    }
    else{
        cout << r;
    }

    return 0;
}