#include <iostream>
using namespace std;
int main()
{
int a,b,c=0;
cin>>a>>b;
for (int i=a;i<=b;i++)
{
int luck=0,x=i;
while (x)
{
if (x%10==4 || x%10==7)
{
x/=10;
}
else {
luck++;
break;
}
}
if(luck==0)
{
cout << i << " ";
c++;
}
}
if(c==0) {
cout << -1;
}
return 0;
}
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