#include <cstdlib>
#include <cmath>
#include <cstring>
#include <cstdio>
#include <string>
#include <iostream>
#include <set>
#include <algorithm>
#define MAXN 0x7fffffff
using namespace std;
int a[200005],b,c,d,l,m,n,t,s;
int main(void)
{
	freopen ("tahort.in","r",stdin);
	freopen ("tahort.out","w",stdout);
	scanf("%d",&b);
	for (c=0;c<b;c++) scanf("%d",&a[c]);
	l=MAXN;
	for (c=0;c<b;c++)
	{
		if (l>=a[c]) 
		{
			l=a[c];
			n=c;
		}
		if (a[c]>d) 
		{
			d=a[c];
			m=d;
		}
	}
	if (m<l) printf("%d",l-m+1);
		else printf("0");
	fclose(stdin);
	fclose(stdout);
	return 0;
}