cin>>N;

for(int i=0; i<N; i++){

int t;

cin>>t;

ops[i] = t;

}

for(int i=N; i>0; i--){

//cout<<"look at "<<i<<endl;

if(ops[i-1] == -1){

op_count[i-1] += op_count[i] + 1;

//cout<<"op_couunt["<<i-1<<" = "<<op_count[i-1]<<endl;

}else{

op_count[i-1] = op_count[i];

}

}

for(int i=0; i<N; i++){

if(ops[i] == 0){

//cout<<"i = "<<i<<" op_count[i] = "<<op_count[i]<<" s_p = "<<s_p<<endl;

if(op_count[i] < s_p){

continue;

}else{

//cout<<"copying"<<endl;

for(int i=0; i<s_p; i++){

mystack[i+s_p] = mystack[i];

}

s_p += s_p;

}

}else if(ops[i] == -1){

//cout<<mystack[s_p-1]<<endl;

printf("%d\n", mystack[s_p-1]);

s_p -= 1;

} else if(ops[i] > 0){

mystack[s_p++] = ops[i];

}

}

return 0;