S = input()

ans = len(S) + 1

for i in range(len(S)):
    
    if S[i] == 'c':
        
        x = 0
        
        for j in range(i + 1, len(S)):
            
            if S[j] == 'w':
                
                x += 1
                
                if x == 2:
                    
                    ans = min(ans, j - i + 1)
                    
                    break

if ans > len(S):
    
    print(-1)
    
else:
    
    print(ans)