program p1250;
 uses math;
 var a,f:array[0..10000]of longint;
     n,i,z,p,l,turn,r,zz:longint;
  begin
   assign(input,'jack.in');
   reset(input);
   assign(output,'jack.out');
   rewrite(output);
   read(n);
   for i:=1 to n do
    read(a[i]);
   for i:=n downto n-4 do
    f[i]:=0;
   for i:=n-5 downto 1 do
    begin
     z:=0;p:=0;
     inc(z,a[i]);inc(z,a[i+2]);
     inc(p,a[i+1]);inc(p,a[i+3]);
     turn:=1;
     r:=i+3;
     while r<n do
     case turn of
      1:begin
         if (z<=16)and(r<n) then begin inc(r); inc(z,a[r]); end;
         if z=21 then begin f[i]:=max(f[i],f[r+1]); break; end;
         if z>21 then begin f[i]:=max(f[i],f[r+1]+1); break; end;
         turn:=0;
        end;
      0:begin
         if (p>z)and(z>16) then begin f[i]:=max(f[i],f[r+1]+1); break; end;
         l:=r;
         zz:=z;
         while (z<=16)and(l<n) do begin inc(l); inc(z,a[l]); end;
         if z>21 then begin f[i]:=max(f[i],f[l+1]+1); break; end
          else if p>z then f[i]:=max(f[i],f[l+1]+1)
           else f[i]:=max(f[i],f[l+1]);
         z:=zz;
         if r<n then
          begin
           inc(r);
           inc(p,a[r]);
          end;
         if p>21 then begin f[i]:=max(f[i],f[r+2]); break; end;
         turn:=1;
         if r=n then
          if(p>z) then begin f[i]:=max(f[i],1); break; end else begin f[i]:=max(f[i],0); break; end;
        end;
     end;
    end;
   write(f[1]);
   close(input);
   close(output);
  end.