s = input()

jorns = []
for i in range(0, len(s)-1, 2):
    f_c = s[i]
    s_c = s[i+1]

    if f_c == '+':
        jorns.append(True)
    else:
        jorns.append(False)

# print(jorns)

# 1. flip False
true_groups = 0
false_groups = 0

sign = jorns[0]

for i, jorn in enumerate(jorns):
    if jorn == sign or i == 0:
        continue
    elif jorn != sign and sign == True: # switched from False to True
        true_groups += 1
        sign = jorn
    elif jorn != sign and sign == False: # swtich from True to False
        false_groups += 1
        sign = jorn

if sign == True:
    true_groups += 1
else:
    false_groups += 1

# print("true_groups: ", true_groups)
# print("false_groups: ", false_groups)

print(min(true_groups, false_groups))