func_code_string: #include <bits/stdc++.h>   using namespace std;   long long mod = 1e9 + 7;   signed main() {     long long n;     cin >> n;     vector<long long> a(n);     vector<long long> ruio(n + 1, 0);     vector<long long> ruit(n + 1, 0);     long long ro = 0;     long long rt = 0;     for (long long i = 0; i < n; i++) {       cin >> a[i];       if (a[i] == 1) {         ro++;       } else {         rt++;       }       ruio[i + 1] = ro;       ruit[i + 1] = rt;     }     long long ans = rt;     for (long long i = 0; i < n; i++) {       long long ltmp = 0;       for (long long j = 0; j < i; j++) {         ltmp = max(ltmp, ruio[j] + (ruit[i + 1] - ruit[j]));       }       long long rtmp = 0;       for (long long j = i; j < n; j++) {         rtmp = max(rtmp, (ruio[j + 1] - ruio[i]) + (ruit[n] - ruit[j]));       }       ans = max(ans, ltmp + rtmp);     }     cout << ans << endl;   }   