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#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double db;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<db> vdb;
typedef vector<pii> vii;
typedef vector<pll> vll;
#define st first
#define nd second
#define sz(x) ((int)x.size())
#define all(x) (x).begin(),(x).end()
#define pb push_back
#define BOOST ios_base::sync_with_stdio(0);cin.tie(0);
#define FOR(i,j,k) for(auto i = (j); i<(k); i++)

constexpr ll INF = 1e15;

int main()
{
    BOOST;
	ll n,m,s;
    cin>>n>>m>>s;

    vll V(m);
    for(auto& e:V) cin>>e.st>>e.nd;
    sort(all(V));


    int i = 0;
    while (s > V[i].nd) i++;

    int j = i;
    while (j > 0 && V[j].st - V[j - 1].nd == 1) j--;
    ll free_before = V[j].st - 1;
    if (free_before == 0) free_before = -INF;

    while (i < m && V[i + 1].st - V[i].nd == 1) i++;
    ll free_after = V[i].nd + 1;
    if (free_after == n + 1) free_after = INF;

    if (abs(s - free_before) <= abs(s - free_after))
        cout<<free_before;
    else
        cout<<free_after;
}