a = [int(i) for i in input().split()]
l = 1
for i in range(len(a)):
    if a[i] != a[i + 1]:
        l += 1
print(l)

a = [1, 2, 3, 4]

range(len(a)) = [0, 1, 2, 3]

если i = 3, то i + 1 = 4  и a[i + 1] получается a[4]