#!/usr/bin/env python3

# Advent Of Code 2020 - Day 3

"""
...#.#..#..#..#..............##
.##.......###.#......#....#..##
..##.##.#......#....#..#...#..#


..##.......
"""

filename = "input.txt"

with open(filename) as f:
    content = f.readlines()

trees = 0

totalRows = len(content)-1
totalColumns = len(content[0])-1

#print (totalColumns)
#print (totalRows)

    
x,y = 0,0
moveRight = 3
moveDown = 1

row = 0

while row < totalRows:
    
    x = x + moveDown
    y = y + moveRight
   

    if y >= totalColumns:
        y = y - totalColumns
#        print (y)

#    print (x, y)
    if content[x][y] == "#":
         trees = trees + 1
    
    row = row +1

print (trees)

"""
0,0
right 3, down 1
+3,+1

check if y is >= len(content)
    print trees result

check if x is >= len(line)
    move to start of the line and continue

"""