s=input()
r=range
a=l=len(s)
f=0
for i in r(0,l):
    for j in r(i,l):
        if s[i]!='c' or s[j]!='w':continue
        t=s[i+1:j]
        if 'w' in t:f,a=1,min(a,len(t)+2)
print(a if f else -1)