def main():
    S = list(input())
    wwc_lengthes = []
    wwc_store = []
    for i in range(len(S) - 1, -1, -1):
        if S[i] == 'w':
            if len(wwc_store) == 1:
                wwc_store.append(i)
            if len(wwc_store) == 0:
                wwc_store.append(i)
        if S[i] == 'c':
            if len(wwc_store) == 2:
                wwc_lengthes.append(wwc_store[0] - i + 1)
                wwc_store = []
    print(min(wwc_lengthes) if wwc_lengthes else -1)


if __name__ == '__main__':
    main()