s=input()
r=range
l=len(s)
m=1000
t=[k-i+1 for i in r(l) for j in r(i+1,l) for k in r(j+1,l) if s[i]+s[j]+s[k]=='cww']
if t:m=min(t)
print(m if m!=1000 else -1)