file = open('17_11887.txt')
A = list(map(int, file.readlines()))
count = 0
for i in range(len(A) + 3):
    B = []
    B += [A[i]]
    B += [A[i-1]]
    B += [A[i-2]]
    B += [A[i-3]]
    B = B.sort()
    if (B[0] // 10 < 10 and B[1] // 10 >= 10) or (B[0] // 10 < 10 and B[3] // 10 < 10):
        count += 1
print(count)