n,m=map(int,input().split())
lst=[]
ans=[]
for _ in range(n):
    tmp=list(map(int,input().split()))
    lst.append(tmp)
for i in range(n):
    for j in range(m):
        ans.append(lst[i][j])
ans.sort()
for i in range(n):
    print(*ans[i*m:(i+1)*m])
# print(ans)