#include <bits/stdc++.h>   using namespace std;   int main() {     int n;     int big = 0, small = 1000000000;     int a[1000];     cin >> n;     for (int i = 0; i < n; i++) {       cin >> a[i];       if (a[i] > big) {         big = a[i];       }       if (a[i] < small) {         small = a[i];       }     }     cout << big - small + 1 - n;   }   