#include <iostream>
#include <cstdio>
using namespace std;
 
    int main() {
        ios_base::sync_with_stdio(false);
        cin.tie(nullptr);
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
int x,y;
        cin>>x>>y;
        bool found=false;
        for(int i=x;i<=y;i++) {
bool c=true;
            int a=i;
 int b=i;
            while (b!=0) {
                a=b%10;
                b/=10;
                if (a==4||a==7){
                    c=true;
            }
else {
    c=false;
    break;
}
            }
 
if(c==true) {
    cout<<i<<" ";
    found=true;
}
        }
        if (found==false) {
            cout<<-1<<endl;
        }
        return 0;}