#include <bits/stdc++.h>
using namespace std;
map<long long, long long> f;
map<long long, long long>::iterator it;
long long a, b, v, ans;
int n;
inline long long gi() {
  register long long x = 0, q = 1;
  register char ch = getchar();
  while ((ch < '0' || ch > '9') && ch != '-') ch = getchar();
  if (ch == '-') q = -1, ch = getchar();
  while (ch >= '0' && ch <= '9') x = x * 10 + ch - '0', ch = getchar();
  return q * x;
}
int main() {
  n = gi(), f[gi() - 1] = 0;
  for (register int i = 2; i <= n; ++i) {
    v = gi();
    while (f.begin() != f.end()) {
      it = f.end(), a = (*(--it)).first;
      b = (*it).second;
      if (a < v) break;
      f[v - 1] = max(f[v - 1], f[a] + (a - a % v - v) * (i - 1));
      f[a % v] = max(f[a % v], f[a] + (a - a % v) * (i - 1)), f.erase(it);
    }
  }
  for (it = f.begin(); it != f.end(); ++it)
    ans = max(ans, (*it).first * n + (*it).second);
  cout << ans;
  return 0;
}
