#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
#define FOR(i,a) for (int i=0;i<(a);++i)
#define FORD(i,a) for (int i=(a)-1;i>=0;i--)
#define FORT(i,a,b) for (int i=(a);i<=(b);++i)
#define FORTD(i,b,a) for (int i=(b);i>=(a);--i)
#define trav(i,v) for (auto i : v)
#define all(v) v.begin(),v.end()
#define ad push_back
#define fr first
#define sc second
#define mpr(a,b) make_pair(a,b)
#define pir pair<int,int>
#define all(v) v.begin(),v.end()
#define make_unique(v) v.erase(unique(all(v),v.end()))
#define fastio ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define dbg(x);
#define dbgv(v);
#define srng mt19937 rng(chrono::steady_clock::now().time_since_epoch().count())
#define y1 EsiHancagorcRepa
#ifdef ALEXPC
#define dbg(x); cout<<#x<<" = "<<x<<endl
#define dbgv(v); cout<<#v<<" = ["; trav(tv,v)cout<<"tv,";cout<<"]"<<endl
#endif
//const int N=100,M=N*N;
const ll MOD=1000*1000*1000+7;
const int N=2*1e6+6,M=6*N,MAXND=N;
const ll MX=1000000000ll*1000000000ll;
typedef struct item * pitem;
struct item{
int key,val,mx;
pitem l,r;
item(pitem _l,pitem _r,int _key,int _val,int _mx){
l=_l;
r=_r;
key=_key;
val=_val;
mx=_mx;
}
int get_mx(pitem v){
if (!v)return 0;
return v->mx;
}
pitem push(int nkey,int nval){
pitem _l=l,_r=r;
int _val=val;
if (nkey<key){
_l=l->push(nkey,nval);
}
else if (nkey==key){
_val=nval;
}
else{
_r=r->push(nkey,nval);
}
return new item(_l,_r,key,_val,max(max(get_mx(_l),get_mx(_r)),_val));
}
int get(int nkey){
//cout<<key<<endl;
if (nkey<key){
return l->get(nkey);
}
else if (nkey==key){
return max(get_mx(l),val);
}
else {
return max(val,max(get_mx(l),r->get(nkey)));
}
}
};
pitem make(int tl,int tr){
if (tl>tr)return NULL;
int tm=(tl+tr)/2;
return new item(make(tl,tm-1),make(tm+1,tr),tm,0,0);
}
pitem ver[N];
int pat[N];
int main(){
fastio;
srng;
int n;
cin>>n;
ver[0]=make(0,n);
FORT(i,1,n){
int tv;
cin>>tv;
if (tv>0){
ver[i]=ver[i-1]->push(0,i);
pat[i]=tv;
}
else{
tv=-tv;
int kpnel=ver[i-1]->get(tv-1)-1;
//cout<<1<<endl;
pat[i]=pat[kpnel];
ver[i]=ver[kpnel]->push(tv,i);
}
cout<<pat[i]<<endl;
}
return 0;
}
/*
3 4
1 2 5
2 3 2
3 1 4
2 3 8
5
2 1 5
2 1 2
2 2 5
2 3 4
2 3 2
*/
