#opt.1

###

# num = [1,2,8,2,1,5,5,0,1,0,7,3]

# count = 0

#for index in range(0,11,1):

# if num[index] + num[index+1] == 10:

# count += 1

#print(count)

#opt.2

#num = [1,2,8,2,1,5,5,0,1,0,7,3]

#count2 = 0

#def duplas(a,b) -> int:

# if a + b == 10:

# return 1

# else:

# return 0

#for index in range(len(num)-1):

# count2 += duplas(num[index], num[index+1])

#print(count2)

#opt. 3

num = [1,2,8,2,1,5,5,0,1,0,7,3]

a = 0

b = 0

total = 0

class duplas:

def __init__(self, a, b):

self.a = a

self.b = b

self.total = 0

#print("a: {}, b: {}".format(a,b))

def cantOf10s(self):

if (self.a + self.b == 10):

self.total += 1

return self.total

for i in range(len(num)-1):

total += duplas(num[i],num[i+1]).cantOf10s()

print(total)