int n = in.nextInt();
int[] a = new int[n];
int[] b = new int[n];
for(int i=0; i<n; i++)
{
    for(int j=0; j<n; j++)
    {
        int x = in.nextInt();
        a[i] += x;
        b[j] += x;
    }
}
String pts = "Possible";
for(int i=0;i<n;i++)
{
    int j=0;
    for(j=i;j<n;j++)
    {
        if(a[i] == b[j])
        {
            int temp = b[j];
            b[j] = b[i];
            b[i] = temp;
            break;
        }
    }
    if(j==n)
    {
        pts = "Impossible";
        break;
    }
}
System.out.println(pts);