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#include <bits/stdc++.h>
using namespace std;
int main()
{
    ios_base::sync_with_stdio(0);
    int m;
    long long n,s,a,b;
    cin>>n>>m>>s;
    vector<pair<long long,long long>> v;
    v.push_back({0,1});
    v.push_back({n,0});
    for(int i=0;i<m;i++)
    {
        cin>>a>>b;
        v.push_back({a,-1});
        v.push_back({b,1});
    }
    sort(v.begin(),v.end());
    long long ind=-1e12;
    for(int i=0;i<=2*m;i++)
    {
        if(v[i+1].first==-1) continue;
        if(v[i].first==n) continue;
        if(v[i].second==1)
        {
            if(v[i].first==v[i+1].first-1 && v[i+1].second!=0) continue;
            if(s<=v[i].first)
            {
                if(abs(s-ind)>abs(s-v[i].first-1))
                {
                    ind=v[i].first+1;
                }
            }
            else if(s>=v[i+1].first)
            {
                if(abs(s-ind)>abs(s-v[i+1].first+1))
                {
                    ind=v[i+1].first-1;
                }
            }
            else
            {
                cout<<s;
                return 0;
            }
        }
    }
    cout<<ind;

}