S = "ilovechiwawa"

def chk_chiwawa(input):
    count_len = 0
    count_cww = 0
    cww_num   = -1
    for i in input:
        if count_cww == 3:
            cww_num = count_len
            break
        if count_cww >= 1:
            if i == "w":
                count_cww += 1
            count_len += 1
            continue
        if i == "c":
            count_cww += 1
            count_len += 1
    return cww_num


if __name__ ==  '__main__':
    output = chk_chiwawa(S)
    print(output, '\n')