If there is no requirement for the straight lines to run all the way across, you can split into two sections of 39 i.e.
Straight line 1: Between 9/10 to the middle
Straight line 2: Between 3/4 to the middle
Area 1 : 10+11+12+1+2+3 = 39
Area 2: 4+5+6+7+8+9 = 39