https://www.acwing.com/problem/content/832/

#include<iostream>
#include<stack>
using namespace std;
const int N = 1e5 + 10;
stack<int> s;
int n, x, y;
int main(){
    cin >> n;
    while(n--){
        cin >> x;
        while(s.empty() == false){
            y = s.top();
            if(y < x) break;
            else s.pop();
        }
        if(s.empty() == true)cout << "-1 ";
        else cout << s.top() << ' ';
        s.push(x);
    }
    return 0;
}