x3462UA6

1#!/usr/bin/env python2.6
2"""(c) gorlum0 [at] gmail.com"""
3from sys import stdin
4MAXN = 10**6
5
6dp = [0] * (MAXN+1)
7dp[0] = 1
8
9for i in xrange(MAXN+1):
10    if dp[i-7]:
11        dp[i] = 7
12    elif dp[i-4]:
13        dp[i] = 4
14
15for n in map(int, stdin):
16    if not dp[n]:
17        print -1; continue
18
19    lucky = []
20    while n:
21        lucky.append(dp[n])
22        n -= dp[n]
23    lucky.reverse()
24    print ''.join(map(str, lucky))