#include <cstdio>

using namespace std;

int sol[5005], bf[5005], v[5005];
int n, i, j, p, s, min;

int main ()
{
    freopen ("subsir2.in", "r", stdin);
    freopen ("subsir2.out", "w", stdout);
    scanf ("%d",&n);
    for (i=1; i<=n; ++i)
        scanf ("%d", &v[i]);
    for (i=n; i>0; --i)
    {
        min = 11111111;
        s = min;
        for (j=i+1; j<=n; ++j)
            if (v[j]>=v[i] && v[j]<min)
            {
                min = v[j];
                if (sol[j] <= s)
                    s = sol[j], p=j;
            }
        if (min = 11111111)
            sol[i] = 1;
        else
            sol[i] = sol[p]+1, bf[i]=p;
    }
    min = sol[1], p=1, j=v[1];
    for (i=2; i<=n; ++i)
        if (v[i] < j)
        {
            j = v[i];
            if (sol[i] <= min)
                min = sol[i], p=i;
        }
        printf ("%d\n%d", min, p);
        while (--min)
        {
            p = bf[p]; printf("%d", p);
        }
        return 0;
}