package main

import (
	"bufio"
	"fmt"
	"os"
)

func main() {
	in := bufio.NewReader(os.Stdin)
	out := bufio.NewWriter(os.Stdout)
	defer out.Flush()

	var n int
	if _, err := fmt.Fscan(in, &n); err != nil {
		return
	}

	present := make([]bool, n+1)
	need := n

	for i := 0; i < n; i++ {
		var x int
		fmt.Fscan(in, &x)
		present[x] = true

		wrote := false
		for need >= 1 && present[need] {
			if wrote {
				out.WriteByte(' ')
			}
			fmt.Fprint(out, need)
			need--
			wrote = true
		}
		out.WriteByte('\n')
	}
}