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#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vll;
typedef vector<vll> vvll;
typedef vector<pii> vpii;
typedef vector<string> vs;
typedef vector<char> vc;
typedef vector<bool> vb;
typedef long double ld;
typedef unordered_map<int, int> umii;
typedef vector<pair<ll,ll>> vpll;
typedef tuple<int,int,int> tp;
const ll MOD = 1e9+696969;


void solve()
{
  ll n, s, m;
  cin >> n >> m >> s;

  vpll part(m);
  for(int i=0; i<m; ++i)
  cin >> part[i].first >> part[i].second;

  sort(part.begin(), part.end());

  vpll free;
  if(part[0].first>1)
    free.push_back({1,part[0].first-1});

    for(int i=0; i<m-1; ++i)
    {
        ll l=part[i].second +1;
        ll r= part[i+1].first -1;
        if(l<=r)
        free.push_back({l,r});
    }

    if(part[m-1].second<n)
    free.push_back({part[m-1].second+1,n});

    ll best = LLONG_MAX;
    ll bestbuild = -1;

    for(auto x:free)
    {
        ll l=x.first;
        ll r=x.second;
        ll cand;
        
        if(s<l)
        cand =l;
        else if(s>r)
        cand = r;
        else
        cand =s;

        ll dist=abs(s-cand);
        if(dist<best or (dist==best and cand < bestbuild))
        {
            best=dist;
            bestbuild=cand;
        }
    }

    cout << bestbuild;
}


int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    solve();
    return 0;
}