Trianglane
Bocchi the Builder has just finished constructing her latest project: a pathway consisting of two rows of white equilateral triangular tiles. However, at the last moment, disaster struck, and she accidentally spilled black paint on some of the tiles! Now, she must purchase warning tape to block off the wet areas. Can you help her determine how many meters of tape she needs?
The first triangle will always point upwards, and any pair of adjacent tiles (that is, tiles that share a common side) will point in opposite directions. Every triangle has a side length of 1 meter.
Input
The first line will consist of one integer, , representing the number of columns.
The next two lines will each consist of integers separated by spaces. Each integer represents the colour of a tile in the room, with 1 indicating that the tile is black and 0 indicating that the tile is white.
Output
Output a single integer representing the length of the tape Bocchi must purchase in meters.
Explanation Input/Output Sample 1:
The tiles are painted as follows, with the warning tape highlighted in yellow.
Figure 1
Explanation Input/Output Sample 2:
The tiles are painted as follows, with the warning tape highlighted in yellow.
Figure 2
| Input Samples | Output Samples |
|---|---|
|
5
1 0 1 0 1 0 0 0 0 0 |
9
|
|
7
0 0 1 1 0 0 0 0 0 1 0 1 0 0 |
8
|