def main():
    s = input()
    ans = []
    c = 0
    
    for i in range(len(s)):
        if s[i] == 'c':
            tmp = i
            c = 0
            for j in range(i+1, len(s)):
                if s[j] == 'w':
                    c += 1
                if c == 2:
                    ans.append(j-i+1)
                    break
    if len(ans) > 0:
        print(min(ans))
    else:
        print(-1)
    
if __name__ == '__main__':
    main()