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#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;
using ll = long long;

int main()
{
//    cin.tie(0)->sync_with_stdio(0);
    ll n, m, s;
    cin>>n>>m>>s;
    vector<pair<ll, ll>> vec(m);
    for(auto& x : vec)
        cin>>x.first>>x.second;
    ranges::sort(vec);
//    for(auto x : vec)
//        cout<<x.first<<".."<<x.second<<"\n";
    int ss = -1;
    for(int i=0; ss==-1; i++)
        if(vec[i].second >= s)
            ss = i;
//    cout<<ss<<";\n";
    ll l = vec[ss].first;
    ll r = vec[ss].second;
    for(int i=ss+1; i<m; i++)
    {
        if(vec[i].first == r+1)
            r = vec[i].second;
        else
            break;
    }
    for(int i=ss-1; i>=0; i--)
    {
        if(vec[i].second == l-1)
            l = vec[i].first;
        else
            break;
    }
//    cout<<l<<".."<<r<<"\n";
    if(r==n)
    {
        cout<<l-1<<"\n";
    }
    else if(l==1)
    {
        cout<<r+1<<"\n";
    }
    else
    {
        if(s-l <= r-s)
            cout<<l-1<<"\n";
        else
            cout<<r+1<<"\n";
    }
}