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

struct St { int a, b; } ;

int const maxn=5000;
 St S[maxn];
int V[maxn];
int L[maxn];

void heap_push ( int i ) {
  int t;
  while ( 0 < i ) {
    t=((i-1)>>1);
    if (S[i].a<=S[t].a) { return; }
    St e=S[i]; S[i]=S[t]; S[t]=e; i=t;
  }
}

void heap_pop ( int n ) {
  St e=S[n]; S[n]=S[0]; S[0]=e;
  int i,t=0;
  while ( n>(i=((1+t)<<1)-1) ) {
    if ( (n>(1+i)) && (S[1+i].a>S[i].a) ) { ++i; }
    if ( S[i].a<=S[t].a) { return; }
    e=S[i]; S[i]=S[t]; S[t]=e; i=t;
  }
}

void heap_sort ( int n ) {
  int s ; for ( s=1; n>s; ++s ) { heap_push(s); }
  for ( s=n-1; s>0; --s ) { heap_pop(s); }
}

int
main ( ) {
  FILE * fs=fopen("secv.in","r"); int N,s,e,t=0,mn=-1,y; fscanf(fs,"%d",&N);
  for ( s=0; N>s; ++s ) { fscanf(fs,"%d",&S[s].a); S[s].b=s; } fclose(fs);
  heap_sort(N);
  s=0; while (N>s) {
    e=S[s].a;
    while ( (N>s) && (S[s].a==e) ) { V[S[s].b]=t; ++s; }
    ++t;
  } --t;
  for ( s=0; N>s; ++s ) { L[s]=-1; }
  for ( s=0; N>s; ++s ) { e=V[s];
    if ( 0==e ) { L[e]=s; } else { L[e]=L[e-1]; }
    if ( (t==e)&&(-1!=L[e]) ) { y=s-L[e]+1;
      if ((-1==mn)||(y<mn)) { mn=y; }
    }
  }
  fs=fopen("secv.out","w"); fprintf(fs,"%d\n",mn); fclose(fs);
  return 0;
}