#include <iostream>
#include <string>
#include <vector>
#include <cassert>
#include <algorithm>
#include <functional>
#include <cmath>
#include <utility>
#include <numeric>
#include <map>
#include <iomanip>
using namespace std;

int rec(int a, int b){
	if(b == 0) return a;
	return rec(b, a%b);
}

int LCM(int a, int b){
	int gcm = rec(a, b);
	return a * b / gcm;
}

int main() {
	int N; cin >> N;
	vector<int> a(N);
	for(iant i = 0; i < N; i++) cin >> a[i];

	int lcm = a[0];
	for(int i = 1; i < N; i++){
		lcm = LCM(lcm, a[i]);
	}

	int ans = 0;
	for(int i = 0; i < N; i++){
		ans += (lcm - 1) % a[i];
	}

	cout << ans << endl;
}