sentence = input()
N = len(sentence)
second = False
min = 101

for i in range(N):
    if sentence[i] == "c":
        count = 1
        for j in range(N-i-1):
            count = count+1
            if sentence[i+j+1] == "w":
                if second == True:
                    if min > count:
                        min = count
                        break
                else:
                    second = True
        second = False

if min == 101:
    min = -1
print(min)