N O R T H
A B C D E F
+---+---+---+---+---+---+
1 | | | 2 | | | | 1
+---+---+---+---+---+---+
2 | | 1 | 3 | 3 | | | 2
+---+---+---+---+---+---+
3 | 1 | 2 | | 1 | | | 3
+---+---+---+---+---+---+
4 | | 3 | | | 3 | | 4
+---+---+---+---+---+---+
5 | | 1 | | | | | 5
+---+---+---+---+---+---+
6 | | 2 | | | 2 | | 6
+---+---+---+---+---+---+
A B C D E F
S O U T H
I think the shortest route for North is C1-D2-E4-B4-B5(via A4,A5)-B6-South's goal, but C1-B2-B3-D3-D2-E4-B4-B5-B6-goal will also win.