#include <bits/stdc++.h>
#define inf INT_MAX
#define NN INT_MIN
typedef long long ll;
using namespace std;
int q[10000000];
int r = 5000000, l = 5000001;
int main()
{
#ifdef WHX_AK_IOI
   freopen("data.in", "r", stdin);
// freopen("dataout.txt","w",stdout);
#endif
   ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
   int T;
   cin >> T;
   while (T--)
   {
      int op;
      cin >> op;
      if (op == 1)
      {
         int x;
         cin >> x;
         q[++r] = x;
      }
      if (op == 2)
      {
         int x;
         cin >> x;
         q[--l] = x;
      }
      if (op == 3)
         r--;
      if (op == 4)
         l++;
      if (op == 5)
      {
         int k, c;
         cin >> k >> c;
         int sum = 0;
         for (int i = 0; i <= c - 1; i++)
            sum += q[r - i * k];
         cout << sum << endl;
      }
      if (op == 6)
      {
         int k, c;
         cin >> k >> c;
         int sum = 0;
         for (int i = 0; i <= c - 1; i++)
            sum += q[l + i * k];
         cout << sum << endl;
      }
   }
   // system("pause");
   return 0;
}