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#include <bits/stdc++.h>
using namespace std;
using ll=long long;
using pr=pair<ll, ll>;
#define nl '\n'
#define st first
#define nd second
#define sz(x) (int)(x).size()
#define each(a, b) for(const auto& a:b)
#define rep(a, b) for(int a=0; a<(b); a++)
#define coz(x) cerr<<"("<<__LINE__<<") "<<(#x)<<": "<<(x)<<'\n'
#define cot(x, l, n) cerr<<"("<<__LINE__<<") "<<(#x)<<": "; \
for(int i=l; i<l+n; i++) { cerr<<x[i]<<' '; } cerr<<'\n'

constexpr int M=1e3+6;

pr lr[M];
set<ll> s;

ll n,a;
int m;

ll dw=1e13;
ll bw=0;

void check(ll b) {
    bool ok=((bool)(s.find(b)==s.end())&(bool)(b>=1)&(bool)(b<=n));
    if(!ok) {
        return;
    }
    ll d=abs(a-b);
    // cerr<<b<<' '<<d<<nl;
    if(d<dw) {
        dw=d;
        bw=b;
    }
}

int main() {
    cin.tie(nullptr)->sync_with_stdio(false);
    cin>>n>>m>>a;
    rep(i, m) {
        cin>>lr[i].st>>lr[i].nd;
    }
    sort(lr, lr+m);
    rep(i, m) {
        s.insert(lr[i].st);
        s.insert(lr[i].nd);
    }
    rep(i, m) {
        check(lr[i].st-1);
        check(lr[i].nd+1);
    }
    cout<<bw<<nl;
}