#include<fstream>
#include <algorithm>
#define dmax 5000
using namespace std;
ifstream fin("secv.in");
ofstream fout("secv.out");
int a[dmax],init[dmax],aux[dmax],i,j,N;
int main ()
{  fin>>N;
int less=5002;
for(i=1;i<=N;i++)
{
fin>>init[i];
a[i]=init[i];
}
    sort(a+1,a+1+N);
    i=2; 
    aux[1]=a[1];
  int  k=1;
    while(i<=N)
    {
    if(a[i]!=a[i-1])
    {++k;
      aux[k]=a[i];
      }
      ++i;
      }
      for(i=1;i<=N;++i)
      { if(init[i]==aux[1])
        { int cont = 0;
          for(j=i;j<=N;++j)
          { if(init[j]==aux[cont+1])
          cont ++;
          if((cont==k) && (j-i+1<=less))
           less=j-i+1;
            }
       } 
  }
           if(less==5002)
           
            fout<<-1; 
             else
            fout<<less<<"\n";
            return 0;
    
    
}