use std::env::args;
use std::fs::File;
use std::io::BufRead;
use std::io::BufReader;

fn get_sinks(map: &Vec<u32>, rows: usize, cols: usize) -> Vec<usize> {
    let mut sinks = vec![];
    for y in 0..rows {
        for x in 0..cols {
            let i = y * cols + x;
            if (x == 0 || map[i] < map[i - 1])
                && (x == cols - 1 || map[i] < map[i + 1])
                && (y == 0 || map[i] < map[i - cols])
                && (y == rows - 1 || map[i] < map[i + cols]) {
                sinks.push(i);
            }
        }
    }
    return sinks;
}

fn main() {
    let path = args().nth(1).unwrap();
    let file = File::open(path).unwrap();

    let mut rows = 0;
    let mut cols = 0;
    let mut map: Vec<u32> = vec![];

    for line in BufReader::new(file).lines() {
        let l = line.unwrap();
        cols = l.len();
        rows += 1;
        for c in l.chars() {
            map.push(c.to_digit(10).unwrap());
        }
    }

    let sinks = get_sinks(&map, rows, cols);

    print!("{}\n", sinks.iter().map(|i| map[*i] + 1).sum::<u32>());
}