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#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for(int i= 0; i<(n); i++)
#define reps(i,s, n) for(int i= (s); i<(n); i++)
#define each(a, x) for (auto &a : x)
#define vv(T) vector<T>
#define endl '\n'
#define sz(x) (int)x.size()
#define ll long long
#define all(c) begin(c), end(c)
#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define pd pair<int,int> 
#define wr cout<<
#define wre wr endl;
#define wrut(a) {each(i,(a))wr i<<" "; wre}
#define wrot(a,b,c) {wre wr a<<" "<<b<<" "<<c<<" ";wre}
#define int ll
const int inf =1e14+7;
bool comp(pd p1,pd p2){
    return p1.se<p2.se;
}
signed main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    int n,m,s;
    int p=-inf,p1=inf;
    cin>>n>>m>>s;
    vv(pd) a(m);
    rep(i,m){
        cin>>a[i].fi>>a[i].se;
    }
    sort(all(a),comp);
    if(a[0].fi-1>0)p=a[0].fi-1;
    if(a[m-1].se+1<=n)p1=a[m-1].se+1;
    reps(i,1,m){
        if(a[i-1].se<a[i].fi-1){
            if(s>a[i-1].se+1)p=a[i-1].se+1;
            else if(a[i-1].se+1<p1)p1=a[i-1].se+1;
            if(s>a[i].fi-1)p=a[i].fi-1;
            else if(a[i].fi-1<p1)p1=a[i].fi-1;
        }
        // cout<<a[i].fi<<" "<<a[i].se<<endl;
    }
    // wr p<<" "<<p1<<endl;
    if(s-p<=p1-s){
        wr p;
    }else{
        wr p1;
    }
}