while True:
    try:
        n = int(input())
        fn = n // 7
        fn7 = n % 7
        m = 0
        while (m*7 +fn7)%4 != 0:
            m +=1
        fn = fn - m
        fn4 = (m*7+fn7)//4
        if(fn>=0):
            print('4'*fn4,'7'*fn,sep='')
        else:
            print('-1')
    except EOFError:
        break