word = input()
gotCww=False
ans=100
w_started=False
w=0
letters=0
cww=False

for i in range(len(word)):
    if word[i]=="c":
        test=word[i::]
        
        for j in range(len(test)):
            letters+=1
            
            if test[j]=="c":
                if not w_started:
                    letters=1

            if test[j]=="w":
                w_started=True
                w+=1
                    
            if w==2:
                cww=True   
                break
    
    if cww:
        gotCww=True
        if letters < ans:
            ans=letters
            
    w_started=False
    w=0
    letters=0
    cww=False
           
                    
if gotCww:
    print(ans)
else:
    print(-1)