def main():
    s = input()
    length_minimom = 'cww'

    for c in range(len(s)):
        if s[c] == 'c':
            count_cww = 0
            for w in range(c+1, len(s)):
                count_cww += 1
                if s[w] == 'w':
                    count_cww == 2
                    length_minimom = min(range(len(s)))
                    break
                    
            if count_cww == 2:
                print(length_minimom)
            else:
                return -1
    
if __name__ == '__main__':
    main()