#include <bits/stdc++.h>
using namespace std;
int const N = 3000;
int n, v[N];
bool prime[100001];
long long go(int x) {
  long long r = 0;
  for (int i = 0; i < n; ++i) {
    r += (x % v[i]);
  }
  return r;
}
int main() {
  scanf("%d", &n);
  int sm = 0;
  for (int i = 0; i < n; ++i) {
    scanf("%d", v + i);
    sm += v[i];
  }
  printf("%d\n", sm - n);
}
