#include<bits/stdc++.h>
using namespace std;
#define INIT  ios_base :: sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define mp make_pair
#define pb push_back
#define ft first
#define sc second
#define ll long long
#define pii pair<int, int>
#define count_bits __builtin_popcount
#define int ll

ifstream fin("secv.in"); ofstream fout("secv.out");
#define cin fin
#define cout fout


int n,a[5010];
int e[5010], b[5010], sir[5010];

int32_t main(){
INIT
cin>>n;
int ln=0;
int res=n;
bool found=false;
set<int> s;
for(int i=1; i<=n; i++){
    cin>>a[i]; s.insert(a[i]);
}

int cnt=s.size();
for(int i=1; i<=n; i++){
    b[0]=i;
    if(ln==0){ln++; sir[ln]=a[i]; b[ln]=i; e[ln]=i; continue;}
    int l=1, r=ln, m=(l+r)/2;
    while(l<r){
        m=(l+r)/2;
        if(sir[m]>=a[i]){
            r=m;
        }
        else{
            l=(m+1);
        }
        m=(l+r)/2;
    }
    if(sir[m]<a[i]){
        ln++; m++;
    }
    sir[m]=a[i]; b[m]=b[m-1]; e[m]=i;
    if(ln==cnt){found=true; res=min(res, e[m]-b[m]+1);}
}
if(!found){cout<<-1; return 0;}
cout<<res;





return 0;
}