#include<stdio.h>
#include<algorithm>
using namespace std;

int v[5002],a[5002],b[5002];

int main()
{
    freopen("secv.in","r",stdin);
    freopen("secv.out","w",stdout);
    int n,i,j,min=5010,aux,k=1;
    scanf("%d",&n);
    for(i=1;i<=n;i++)
    {
        scanf("%d",&v[i]);
        a[i]=v[i];
    }
    sort(v+1,v+1+n);
    b[1]=v[1];
    for(i=2;i<=n;++i)
        if(v[i]!=v[i-1])
            b[++k]=v[i];

    for(i=1;i<=n;++i)
    {
        if(a[i]==b[1])
        {
            aux=0;
            for(j=i;j<=n;++j)
            {
                if(a[j]==b[aux+1])
                    ++aux;
                if(aux==k&&j-i+1<=min)
                    min=j-i+1;
            }
        }
    }

    if(min==5010)
        min=-1;
    printf("%d\n",min);
}