#include<stdio.h>
#include<algorithm>

using namespace std;
 
long v[5002],n,i,j,k=1,aux,minim=5001,a[5002],b[5002];

int main()
{
    freopen("secv.in","r",stdin);
    freopen("secv.out","w",stdout);
    
    scanf("%ld",&n);
    for(i=1;i<=n;i++)
        scanf("%ld",&v[i]);
	
	memcpy(a,v,sizeof(v));
	
    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<=minim)
                    minim=j-i+1;
            }
        }
    }
	
	if(minim!=5001)
		printf("%ld\n",minim);
	else
		printf("-1\n");
	return 0;
}