s=input()
def f(x):
    if x[0]=='c':
        w=0
        for i,j in enumerate(x[1:]):
            if j=='w':w+=1
            if w==2:return i+2
print(min(l) if (l:=[f(s[i:]) for i in range(len(s)) if f(s[i:])]) else-1)