#include<iostream>
#include<cstdio>
#include<string>
#include<vector>
#include<algorithm>
using namespace std;
vector<int> vec;
int gcd(long long  a, int b)
{
	if (b == 0)
		return a;
	return gcd(b, a%b);
}

long long lcm(long long a, int b)
{
	return long long(a*b) / gcd(a, b);
}

int f(long long  m, int i)
{
	if (i == 0)
		return m%vec[i];
	return f(m, i - 1) + m%vec[i];
}

int main()
{
	int n;
	scanf("%d", &n);
	vec.resize(n);
	for (int i = 0; i < n; i++)
		scanf("%d", &vec[i]);
	long long lc = lcm(vec[0], vec[1]);
	for (int i = 2; i < vec.size(); i++)
	{
		lc = lcm(lc, vec[i]);
	}
	cout << f(lc-1, n - 1);
	return 0;
}