#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
multiset<ll>::iterator itt;
const int N = 2e5+111, P = 998244353;

int n;
int a[N];
unordered_map<int, int> mp;

void work(){
	scanf("%d",&n);
	int minn = n + 11;
	for(int i=1;i<=n;i++){
		scanf("%d",&a[i]);
		if(mp[a[i]]) minn = min(minn, i - mp[a[i]] + 1);
		mp[a[i]] = i;
	} if(minn == n + 11) minn = -1;
	printf("%d\n",minn);
}

int main(){
	int t = 1;  //scanf("%d",&t);
	while(t--) work(); return 0;
}