#include <iostream>
using namespace std;
int n, t, kq = 1, kt = 9;
int main()
{
    cin >> n >> t;
    while(--n)
    {
        kq *= 10;
        kt = kt*10 + 9;
    }
    for(kq; kq <= kt; kq++)
        if(kq % t == 0)
        {
            cout << kq;
            exit(0);
        }
    cout << -1;
    return 0;
}

$#khanhtaon$

#include <iostream>
using namespace std;
int main() {
    int n, t;
    cin >> n >> t;    
    int kq = 1;
    for (int i = 1; i < n; ++i) {
        kq *= 10;
    }  
    for (int i = kq; i <= kq * 10 - 1; ++i) {
        if (i % t == 0) {
            cout<<i;
            return 0;
        }
    }    
    cout<<-1;
    return 0;
}