#include <bits/stdc++.h>
using namespace std;
long long n;
long long e[100005];
long long dp[100005][2];
int main() {
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> e[i];
  }
  dp[1][0] = abs(e[1] + 1);
  dp[1][1] = abs(e[1] - 1);
  for (int i = 2; i <= n; i++) {
    dp[i][0] = min(dp[i - 1][0] + abs(e[i] - 1), dp[i - 1][1] + abs(e[i] + 1));
    dp[i][1] = min(dp[i - 1][0] + abs(e[i] + 1), dp[i - 1][1] + abs(e[i] - 1));
  }
  cout << dp[n][1] << endl;
  return 0;
}
