#include <fstream>
#include <vector>
#include <algorithm>
using namespace std;
ifstream f("secv.in");
ofstream g("secv.out");
int N, i, j, x, res = 100000000;
vector<int>a;
int main()
{
    f>>N;
    for(i=0;i<N;++i)
    {
        f>>x;
        a.push_back(x);
    }
    vector <int> b = a;
    sort(b.begin(),b.end());
    b.resize(unique(b.begin(),b.end())-b.begin());
    for(i=0;i<N;++i)
    {
        int poz=0;
        for(j=i;j<N;++j)
        {
            if(a[j]==b[poz]) poz++;
            if(poz==b.size())
            {
                res=min(res,j-i+1);
                break;
            }
        }
    }
    if(res == 1000000000) res=-1;
        g<<res;
    return 0;
}