# your code goes here
def quebracabecas(lista):
teste_set = set(range(lista[0],lista[-1]))
for i in lista:
if i in teste_set:
teste_set.remove(i)
return teste_set
print(quebracabecas([2, 4, 3])) # deveria retornar "1"
print(quebracabecas([3, 1])) # deveria retornar "2"
IyB5b3VyIGNvZGUgZ29lcyBoZXJlCmRlZiBxdWVicmFjYWJlY2FzKGxpc3RhKToKICAgIHRlc3RlX3NldCA9IHNldChyYW5nZShsaXN0YVswXSxsaXN0YVstMV0pKQogICAgZm9yIGkgaW4gbGlzdGE6CiAgICAgICAgaWYgaSBpbiB0ZXN0ZV9zZXQ6CiAgICAgICAgICAgIHRlc3RlX3NldC5yZW1vdmUoaSkKICAgICAgICAKICAgIHJldHVybiB0ZXN0ZV9zZXQKCnByaW50KHF1ZWJyYWNhYmVjYXMoWzIsIDQsIDNdKSkgIyBkZXZlcmlhIHJldG9ybmFyICIxIgpwcmludChxdWVicmFjYWJlY2FzKFszLCAxXSkpICMgZGV2ZXJpYSByZXRvcm5hciAiMiI=