#include<bits/stdc++.h>
#include<atcoder/all>
#define rep(i,n) for(int i=0;i<n;i++)
using namespace std;
using namespace atcoder;
typedef long long ll;
typedef vector<int> vi;
typedef vector<long long> vl;
typedef vector<vector<int>> vvi;
typedef vector<vector<long long>> vvl;
typedef pair<int,int> P;
typedef long double ld;

int main(){
	int n;
	cin >> n;
	vl a(n);
	rep(i, n) cin >> a[i];
	ll base = 0;
	rep(i, n) base += a[i] % a[(i + 1) % n];
	ll ans = base;
	for(int i = 0; i < n - 1; i++){
		ll tmp = base;
		tmp -= a[i] % a[(i + 1) % n];
		tmp -= a[n - 1] % a[0];
		tmp += a[n - 1] % a[i];
		tmp += a[i] % a[0];
		ans = max(tmp, ans);
//		cout << tmp << "\n";
	}
	cout << ans;
	return 0;
}