use std::env;
use std::fs;

fn main() {
    let input = fs::read_to_string(&env::args().nth(1).unwrap()).unwrap();
    let forest: Vec<Vec<i8>> = input.lines()
        .map(|line| line.chars()
            .map(|c| c.to_digit(10).unwrap() as i8).collect())
        .collect();
    let nrows = forest.len();
    let ncols = forest[0].len();

    let min_from_left: Vec<Vec<i8>> = forest.iter()
        .map(|row| row.iter()
            .scan(-1, |h, &tree| {
                let old = *h; *h = i8::max(*h as i8, tree); Some(old)
            })
            .collect())
        .collect();

    let min_from_right: Vec<Vec<i8>> = forest.iter()
        .map(|row: &Vec<i8>| row.iter()
            .rev()
            .scan(-1, |h, &tree| {
                let old = *h; *h = i8::max(*h as i8, tree); Some(old)
            })
            .collect::<Vec<i8>>().iter()
            .rev().map(|x| *x)
            .collect())
        .collect();

    let mut min_from_top: Vec<Vec<i8>> = vec![vec![-1; ncols]; nrows];
    for c in 0..ncols {
        for r in 1..nrows {
            min_from_top[r][c] = i8::max(min_from_top[r-1][c], forest[r-1][c]);
        }
    } 

    let mut min_from_bot: Vec<Vec<i8>> = vec![vec![-1; ncols]; nrows];
    for c in 0..ncols {
        for r in (0..nrows-1).rev() {
            min_from_bot[r][c] = i8::max(min_from_bot[r+1][c], forest[r+1][c]);
        }
    } 

    let mut sum = 0;
    for r in 0..nrows {
        for c in 0..ncols {
            if forest[r][c] > min_from_left[r][c]
                || forest[r][c] > min_from_right[r][c]
                || forest[r][c] > min_from_top[r][c]
                || forest[r][c] > min_from_bot[r][c] {
                sum += 1;
            }
        }
    }
    println!("{:?}", sum);
}