#Бинарный поиск
def binar(akr, key):
midd = 0
left = 0
right = len(akr) - 1
while right - left > 1:
midd = (left + right)//2
if key < akr[midd]: right = midd
else: left = midd
if akr[right] == key:
return right
else:
return -1