func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 1e5 + 9;   int n;   long long a[N], l[N], r[N];   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     cout.tie(NULL);     cin >> n;     for (int i = 1; i <= n - 1; ++i) cin >> a[i];     long long tmp;     l[1] = 0;     for (int i = 2; i <= n; ++i) {       tmp = (a[i - 1] % 2 == 0) ? a[i - 1] : a[i - 1] - 1;       if (a[i - 1] >= 2) l[i] = l[i - 1] + tmp;     }     r[n] = 0;     for (int i = n - 1; i >= 1; --i) {       tmp = (a[i] % 2 == 0) ? a[i] : a[i] - 1;       if (a[i] >= 2) r[i] = r[i + 1] + tmp;     }     tmp = 0;     long long delta;     long long res = 0;     for (int i = n - 1; i >= 1; --i) {       delta = (a[i] % 2 == 0) ? a[i] - 1 : a[i];       tmp = max(tmp + delta, r[i]);       res = max(res, l[i] + tmp);     }     cout << res;   }   