Messages

while True:
    is_end = False
    msg = ''
    occur_c = False
    occur_o = False
    occur_n = False

    while occur_c == False or occur_o == False or occur_n == False:
        sym = input()
        if sym == 'End':
            is_end = True
            break
        if sym[0] == 'c' and occur_c == False:
            occur_c = True
            continue
        elif sym[0] == 'o' and occur_o == False:
            occur_o = True
            continue
        elif sym[0] == 'n' and occur_n == False:
            occur_n = True
            continue

        if (sym[0] >= 'a' and sym[0] <= 'z') or (sym[0] >= 'A' and sym[0] <= 'Z'):
            msg += sym[0]

    if is_end == True:
        break
    print(f'Message: {msg}')