#7 至 #10 WA了 神犇帮忙调一下（必关）

#include <iostream>
#include <algorithm>
using namespace std;
int a[100010],n;
int main(){
	cin>>n;
	for(int i=1;i<=n;i++){
		cin>>a[i];
	}
	int minn=1e9+7,key=0;
	sort(a+1,a+n+1);
	for(int i=1;i<n;i++){
		if(a[i]+1==a[i+1]){
			key++;
		}
		else{
			key++;
			minn=min(minn,key);
			key=0;
		}
	}
	if(a[n-1]+1==a[n]){
		key++;
		minn=min(minn,key);
	} 
	cout<<minn<<endl;
	return 0;
}