#include <iostream>
#include <algorithm>
using namespace std;

int n;
int a[100005], f[100005];

bool cmp(int a, int b){
	return (a>b);
}

int main(){
	cin >> n;
	for (int i = 1;i <= n; i++){
		cin >> a[i];
		//b[i] = a[i];
	}
//	sort(a+1, a+n+1, cmp);
	//string s="";
	int j = n;
	for (int i = 1; i <= n; i++){
		if (a[i]!=j) f[a[i]] = 1;
		else{
			cout << j << " ";
			j--;
			while(f[j]){
				cout << j << " ";
				j--;
			}
		}
		cout << endl;
	}
	return 0;
}