import std.conv, std.functional, std.range, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.bitmanip, std.complex, std.container, std.math, std.mathspecial, std.numeric, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }

string COLOR(string s = "") { return "\x1b[" ~ s ~ "m"; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }


long calc(const(int[]) as) {
  const n = cast(int)(as.length);
  long ret;
  foreach (i; 0 .. n) {
    ret += as[i] % as[(i + 1) % n];
  }
  return ret;
}

void main() {
  try {
    for (; ; ) {
      const N = readInt;
      auto A = new int[N];
      foreach (i; 0 .. N) {
        A[i] = readInt;
      }
      
      const base = calc(A);
      long ans = base;
      foreach (i; 1 .. N - 1) {
        long score = base;
        score -= A[i - 1] % A[i];
        score -= A[i] % A[i + 1];
        score += A[i - 1] % A[i + 1];
        score -= A[N - 1] % A[0];
        score += A[N - 1] % A[i];
        score += A[i] % A[0];
        chmax(ans, score);
      }
      writeln(ans);
      
      debug {
        long brt;
        int[][] ass;
        {
          auto as = A.dup;
          do {
            const score = calc(as);
            if (chmax(brt, score)) ass = [];
            if (brt == score) ass ~= as.dup;
          } while (as[1 .. N].nextPermutation);
        }
        /*
        writeln("brt = ", brt);
        foreach (as; ass) {
          writeln(as);
        }
        //*/
        if (ass[0] != A) {
          writeln(brt, " ", ass);
        }
        assert(brt == ans, format("%s: %s %s; %s", A, brt, ans, ass));
      }
    }
  } catch (EOFException e) {
  }
}