#include<bits/stdc++.h>
using namespace std;

#define all(v) v.begin(),v.end()
using ll = long long;
using ull = unsigned long long;
using vll=vector<ll>;
using vvll = vector<vector<ll>>;


int main(){
    ll N;
    cin>>N;
    vll A(N);
    for(int i=0;i<N;i++){
        cin>>A[i];
    }
    set<ll> st;
    ll ans=0;
    for(int i=N-1;i>=0;i--){
        st.insert(A[i]);
        auto x=st.lower_bound(A[i]);
        if(x==st.begin())continue;
        x--;
        ans=max(ans,*x);
    }
    cout << ans << endl;
}