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

set<pair<ll,ll>> przedz;

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    ll n, m, s;
    cin >> n >> m >> s;
    ll a, b;
    ll preva = -1;
    ll prevb = -1;
    vector<pair<ll,ll>> wej;
    for(int i = 1; i <= m; ++i){
        cin >> a >> b;
        wej.push_back({a,b});
    }
    sort(wej.begin(),wej.end());
    for(int i = 1; i <= m; ++i){
        a = wej[i-1].first;
        b = wej[i-1].second;
        if(prevb == a-1){
            przedz.erase({preva, prevb});
            prevb = b;
            przedz.insert({preva, prevb});
        }
        else{
            przedz.insert({a,b});
            preva = a;
            prevb = b;
        }
    }
    auto it = przedz.upper_bound({s, 1e13});
    --it;
    if(it->first == 1){
        cout << it->second + 1 << "\n";
    }   
    else if(it->second == n){
        cout << it->first - 1 << "\n";
    }
    else{
        ll i1 = it->first - 1;
        if(abs(s - i1) > abs(s - (it->second + 1))){
            i1 = it->second + 1;
        }
        cout << i1 << "\n";
    }
    return 0;
}