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#ifndef LOCAL
#pragma GCC optimize("O3")
#endif
#include <bits/stdc++.h>
#define FOR(i,p,k) for(int i=(p);i<=(k);++i)
#define REP(i,n) FOR(i,0,(n)-1)
#define RFOR(i,p,n) for(int i=(p);i>=(n);--i)
#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()
#define ssize(x) int((x).size())
#define fi first
#define se second
#define V vector
#define pb push_back
#define eb emplace_back
#define C const
#define pn printf("\n")
using namespace std;
typedef long long ll;
typedef V<int> vi;
typedef V<ll> vll;
typedef const int ci;
typedef const ll cll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
void chmin(auto &a, auto b){a=min(a,b);}
void chmax(auto &a, auto b){a=max(a,b);}
ci inf = 2.1e9;
cll infll = 4.5e18;

int I(){
    int z;
    scanf("%d", &z);
    //cin >> z;
    return z;
}

void answer(){
    ll n;
    scanf("%lld", &n);
    int m = I();
    ll s;
    scanf("%lld", &s);

    V<pll> wej(m);
    for(auto &[a, b] : wej) scanf("%lld%lld", &a, &b);
    sort(all(wej));

    ll wyn = infll;
    auto polepsz = [&](ll poz){
        if(abs(poz-s) < abs(wyn-s)) wyn = poz;
        else if(abs(poz-s) == abs(wyn-s)) chmin(wyn, poz);
    };

    REP(i, m){
        ll poz = wej[i].fi-1;
        if(poz >= 1 && (!i || wej[i-1].se < poz)) polepsz(poz);
        poz = wej[i].se+1;
        if(poz <= n && (i==m-1 || wej[i+1].fi > poz)) polepsz(poz);
    }
    printf("%lld\n", wyn);
}

int main(){
    //ios_base::sync_with_stdio(0);
    //cin.tie(0);
    int tt = 1;
    //tt = I();
    while(tt--) answer();
}