Giới thiệu
include <bits/stdc++.h>
using namespace std;
int n, scx = 1, sgh = 9;
int main()
{
ios::sync_with_stdio(0);
cin.tie();
cout.tie();
cin >> n;
n--;
while(n--)
{
scx *= 10;
sgh = (sgh * 10) + 9;
}
while(scx < sgh)
{
if(scx % 3 == 0 && scx % 7 == 0)
{
cout << scx;
exit(0); //
}
scx++;
}
cout << -1;
return 0;
}