#include<cstdio>
#include<algorithm>
#include<vector>
using namespace std;

const int N=5010;
vector < pair<int , int> > x(N);
int v[N],p[N],val;

int main()
{
	freopen("secv.in","r",stdin);
	freopen("secv.out","w",stdout);
	int n,i,r=N;
	scanf("%d",&n);
	for(i=1;i<=n;i++)
	{
		scanf("%d",&x[i].first);
		x[i].second=i;
	}
	sort(&x[1],&x[n+1]);
	v[x[1].second]=1;
	val=1;
	for(i=2;i<=n;i++)
	{
		if(x[i].first!=x[i-1].first)
			++val;
		v[x[i].second]=val;
	}
	for(i=1;i<=n;i++)
	{
		if(v[i]==1)
			p[v[i]]=i;
		else
			p[v[i]]=p[v[i]-1];
		if(v[i]==val)
		{
			if(p[v[i]]!=0)
				r=min(r,i-p[v[i]]+1);
		}
	}
	if(r==5010)
		printf("-1");
	printf("%d\n",r);
	/*for(i=1;i<=n;i++)
		printf("%d %d\n",x[i].first,x[i].second);
	for(i=1;i<=n;i++)
		printf("%d ",p[i]);
	printf("%d",val);*/
	return 0;
}