#!/usr/bin/env python3
import sys
import heapq

def solve():
    input_data = sys.stdin.read().split()
    n = int(input_data[0])
    f = int(input_data[1])
    
    p = [int(x) for x in input_data[2:]]
    
    queues = [[] for _ in range(f + 1)]
    pq = []
    
    for i in range(1, f + 1):
        heapq.heappush(pq, (0, i))
        
    for weight in p:
        total_w, idx = heapq.heappop(pq)
        queues[idx].append(weight)
        heapq.heappush(pq, (total_w + weight, idx))
        
    for i in range(1, f + 1):
        print(" ".join(map(str, queues[i])))

if __name__ == '__main__':
    solve()