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#include<bits/stdc++.h>
using namespace std;
vector<pair<long long,long long>> values;
vector<pair<long long,long long>> values2;
int main()
{
    ios_base::sync_with_stdio(0);
    long long n,m,s,a,b;
    cin>>n>>m>>s;
    for(int i=0;i<m;i++)
    {
        cin>>a>>b;
        values.push_back(make_pair(a,b));
    }
    sort(values.begin(), values.end());
    // for(auto p : values)
    // {
    //    // cerr<<p.first<<" "<<p.second<<endl;;
    // }
    pair<long long, long long> previous = values[0];
    for(int i=1;i<values.size();i++)
    {
        if(previous.second+1 == values[i].first)
        {
            previous.second = values[i].second;
        }
        else
        {
            // cerr<<previous.first<<" "<<previous.second<<" "<<values[i].first<<" "<<values[i].second<<endl;
            values2.push_back(previous);
            previous = values[i];
        }
    }
    values2.push_back(previous);
    for(auto p : values2)
    {
        // cerr<<p.first<<" "<<p.second<<endl;;
        if (p.first<=s && p.second>=s)
        {
            if(p.first-1!=0 && (s-p.first<=p.second-s || p.second==n))
                cout<<p.first-1<<endl;
            else
                cout<<p.second+1<<endl;
            return 0;
        }
    }
}