H, W = map(int, input().split())
l = []

for _ in range(H):
    l += list(map(int, input().split()))

l.sort()
ans = [[-1]*W for _ in range(H)]

for i in range(H):
    for j in range(W):
        ans[i][j] = l[i*W+j]

for ans_i in ans:
    print(*ans_i)