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

const int N=5005;

pair <int,int> x[N];
int v[N];
int poz[N];

int min(int x,int y)
{
	if(x<y)
		return x;
	return y;
}

int main()
{
	freopen("secv.in","r",stdin);
	freopen("secv.out","w",stdout);
	int n,i,val,r=6000;
	scanf("%d",&n);
	for(i=1;i<=n;i++)
	{
		scanf("%d",&x[i].first);
		x[i].second=i;
	}
	sort(&x[1],&x[n+1]);
	val=1;
	v[x[1].second]=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)
			poz[1]=i;
		else
			poz[v[i]]=poz[v[i]-1];
		if(v[i]==val && poz[val])
				r=min(r,i-poz[v[i]]+1);
	}
	if(r==6000)
		printf("-1\n");
	else
		printf("%d\n",r);
	
	return 0;
}