#!/bin/node

const fs = require('fs');

fs.readFile('input.txt', (err, data) => {
    const lines = data.toString().split('\n').filter(l => l.length > 0);
    width = lines[0].length;

    const slopes = [
        [1, 1],
        [3, 1],
        [5, 1],
        [7, 1],
        [1, 2],
    ];
    const positions = slopes.map(_ => 0);
    const results = slopes.map(_ => 0);
	
    for (let i = 0; i < lines.length; i++) {
        const line = lines[i];

        for (let j = 0; j < slopes.length; j++) {
            const [right, down] = slopes[j];

            if (i % down === 0) {
                if (line[positions[j]] === '#') results[j]++;

                positions[j] = (positions[j] + right) % width;
            }
        }
    }

    console.log(results, results.reduce((a, n) => a * n, 1));
});