def main():
    N = int(input())
    num_dic = {2:0, 3:0, 5:0, 7:0}

    while N % 2 == 0:
        N = N / 2
        num_dic[2] += 1

    while N % 3 == 0:
        N = N / 3
        num_dic[3] += 1

    while N % 5 == 0:
        N = N / 5
        num_dic[5] += 1

    while N % 7 == 0:
        N = N / 7
        num_dic[7] += 1

    #print(num_dic)

    ans = ""
    if num_dic[7] != 0:
        ans = ans + str(8) * num_dic[7] 
    if num_dic[3] != 0:
        ans = ans + str(7) * num_dic[3] 
    if num_dic[5] != 0:
        ans = ans + str(5) * num_dic[5] 
    if num_dic[2] != 0:
        ans = ans + str(1) * num_dic[2] 

    print(ans)

if __name__ == '__main__':
    main()