def same(p1, p2):
	p2 = [p2[1], p2[0]]
	# print(p1, p2)
	return p1[0].lower() == p2[0].lower() and p1[1].lower() == p2[1].lower()

s = input().split("!")
nodes = []
edges = []
nodes.append(s[0])
for t in s[1:]:
	newedge = [nodes[-1], t]
	if (nodes[-1].lower() == t.lower()): continue
	# print(newedge)
	if len(edges) > 0 and same(edges[-1], newedge):
		edges.pop()
		nodes.pop()
	else:
		edges.append(newedge)
		nodes.append(t)

print('!'.join(nodes))