from collections import deque
h,w=map(int,input().split())
a=[]
for i in range(h):
    for j in list(map(int,input().split())):
        a.append(j)
a.sort()
a=deque(a)
for i in range(h):
    b=[]
    for j in range(w):
        b.append(a.popleft())
    print(*b)