def main():
    s = input()
    min_length = float('inf')
    for i in range(len(s)):
        if s[i] == 'c':
            count_w = 0
            for j in range(i+1, len(s)):
                if s[j] == 'w':
                    count_w += 1
                    if count_w == 2:
                        min_length = min(min_length, j - i + 1)
                        break
    if min_length == float('inf'):
        print(-1)
    else:
        print(min_length)

if __name__ == '__main__':
    main()