S=input()
w_count=0
max_count=0
c_index,w_index=0,0
for i,st in enumerate(S):
    if st=="c":
        c_index=i
        if w_count>=1:
            w_count=0
    elif st=="w":
        w_count+=1
        if w_count==2:
            w_index=i
            max_count=max(max_count,(w_index-c_index))
            w_count=0
print((max_count+1) if max_count!=0 else -1)