import java.io.*;
import java.util.*;
class Main {
    static final int INF = 987654321;
    static int n, arr[][], cache[][];
    public static void main(String[] args) throws Exception {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st;
        n = Integer.parseInt(br.readLine());
        arr = new int[n][n];
        cache = new int[n][n];
        for(int i=0; i<n; ++i){
            Arrays.fill(cache[i], -1);
            st = new StringTokenizer(br.readLine());
            for(int j=0; j<n; ++j){
                arr[i][j] = Integer.parseInt(st.nextToken());
            }
        }
        System.out.println(solution(0, 0));
    }
    static int solution(int x, int y){
        if(x >= n || y >= n) return INF;
        if(x == n-1 && y == n-1) return 0;
        if(cache[x][y] > 0) return cache[x][y];
        int right = INF, down = INF, ret_right = 0, ret_down = 0;
        if(y + 1 < n) right = arr[x][y+1] - arr[x][y] > 0 ? arr[x][y+1] - arr[x][y] : 0;
        if(x + 1 < n) down = arr[x+1][y] - arr[x][y] > 0 ? arr[x+1][y] - arr[x][y] : 0;
        ret_right = right + solution(x, y + 1);
        ret_down = down + solution(x + 1, y);
        return cache[x][y] = Math.min(ret_right, ret_down);
    }
}