#include <iostream>
#include <fstream>
#include<algorithm>
using namespace std;
ifstream f("secv.in");
ofstream g("secv.out");
int n,a[5001],b[5001],c[5001],k,res=5001;
int main()
{int i,j,p;
f>>n;
for(i=1;i<=n;i++) {f>>a[i];b[i]=a[i];}
sort(b+1,b+n+1);
k=1;c[k]=b[1];
for(i=2;i<=n;i++) if (b[i]!=c[k]) {k++;c[k]=b[i];}
//for(i=1;i<=k;i++) cout<<c[i]<<" ";
for(i=1;i<=n;i++)
if (a[i]==c[1])
{p=2;
for(j=i+1;j<=n;j++) if (a[j]==c[p]) {p++; if (p==k+1) {if (j-i+1<res) res=j-i+1; break;} }
}
if (k==1) res=1;
if (res!=5001) g<<res; else g<<"-1";
return 0;
}