#include <fstream>
#include <algorithm>
using namespace std;
ifstream fin("secv.in");
ofstream fout("secv.out");
const int oo = 10000;
int N, nr, minim = oo, A[5010], B[5010], C[5010];

int main()
{
    fin >> N;
    for (int i=1; i<=N; i++) fin >> A[i], B[i] = A[i];
    sort (B+1, B+1+N);

    for (int i=1; i<=N; i++)
    {
        C[++nr] = B[i];
        while (B[i] == B[i+1] && i<=N) i++;
    }

    for (int i=1; i<=N; i++)
    {
        if (A[i] == C[1])
        {
            int num = 1;
            if (nr == num) minim = num;

            for (int j=i+1; j<=N; j++)
            {
                if (A[j] == C[num+1]) num++;
                if (nr == num)
                {
                    minim = min(minim, j-i+1);
                    break;
                }
            }
        }
    }

    if (minim != oo) fout << minim << '\n';
    else fout << "-1\n";
    fout.close();
    return 0;
}