Insert Whitespace

#n,h,W,p = 2,6,33,5
n,h,W,p = map(int, input().split())

s = """Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.""".split("\n")

def maplines(l, li=0, o=[], s=0):
	if len(l) == li: return [o]

	out = []
	for k in l[li].keys():
		lenv = s + k
		if lenv < h and h - lenv >= 2 or lenv % h == 0:
			o1 = list(o)
			o1.append(k)
			for a in maplines(l, li+1, o1, lenv):
				out.append(a)
		elif lenv > h and lenv%h >= 2:
			lenv = lenv - lenv//h * h
			o1 = list(o)
			o1.append(k)
			for a in maplines(l, li+1, o1, lenv):
				out.append(a)

	return out
		
		

def addsp(w, wi=0, l=None, s=p):
	#if l == None: l = [p]
	if wi == len(w): return [l]

	l.append(w[wi])
	s += w[wi]
	wi += 1
	if s == W or wi == len(w): 
		l.append(0)
		return addsp(w, wi, l, s=0)
	elif s > W: return []

	l2 = list(l)
	s2 = s
	l.append(1)
	s += 1
	if s == W:
		return []
		l.append(0)
		return addsp(w, wi, l, s=0)
	l2.append(2)
	s2 += 2

	lo = []	
	for add in addsp(w, wi, l, s):
		lo.append(add)
	if s2 != W:
		#l2.append(0)
		for add in addsp(w, wi, l2, s2):
			lo.append(add)
	return lo
	

def getout(l):
	global dl
	o = []
	a = ""
	for i in range(len(dl)):
		o.append(dl[i][l[i]])
#	print(o)
	linecount = 0
	for i in range(len(o)):
		a += o[i].pop(0)*" "
		isword = True
		wordi = 0
		for el in o[i]:
			if el == 0:
				a += "\n"
				isword = True
				linecount += 1
				if linecount == h:
					linecount = 0
					a += "#\n"
				continue
			if isword:
				a += prgs[i][wordi]
				wordi += 1
			else:
				a += el * " "
			isword = not isword
	return a
			


prgs = []
dl = []
for _ in range(n):
	prg = input().split()
#	prg = s.pop(0).split()

	prgs.append(prg)
#	print("\n\n") 
#	print(prg)
	pgrl = list(map(len, prg))
#	print(pgrl)
	pos = addsp(pgrl, l=[p])
#	print(pos)
#	print(p)
#	input()
#	if pos == []:
#		print("IMPOSSIBLE")

	d = {}
	for P in pos:
		c = P.count(0)
		if c not in d:
			d[c] = P
	dl.append(d)
ans = maplines(dl)
if ans == []:
	print("IMPOSSIBLE")
else:
	print(getout(ans[0]).rstrip("\n#"))
#print(ans)

	
	

	
	

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: WRONG ANSWER

Test 5

Verdict: TIME LIMIT EXCEEDED

Test 6

Verdict: TIME LIMIT EXCEEDED

Test 7

Verdict: TIME LIMIT EXCEEDED

Test 8

Verdict: TIME LIMIT EXCEEDED

Test 9

Verdict: TIME LIMIT EXCEEDED

Test 10

Verdict: TIME LIMIT EXCEEDED

Test 11

Verdict: TIME LIMIT EXCEEDED

Test 12

Verdict: TIME LIMIT EXCEEDED

Test 13

Verdict: TIME LIMIT EXCEEDED