#include <algorithm>
#include <cassert>
#include <cstdio>
#include <cmath>
#include <deque>
#include <iostream>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <vector>
#include <set>

using namespace::std;


int main() {
  ios::sync_with_stdio(false);
  int n;
  cin >> n;
  int a;
  for (int i = 0; i < n; ++i) {
    cin >> a;
  }
  cout << a - n << endl; 
  
  

  
  return 0;
}