BAEKJOON_14442

import java.io.*;
import java.util.*;
public class Main {
    int x;
    int y;
    int dist;
    int wall;

    public Main(int x, int y, int dist, int wall) {
        this.x = x;
        this.y = y;
        this.dist = dist;
        this.wall = wall; 
    }

    static int N;
    static int M;
    static int K;

    static boolean[][][] visit;
    static int[][] board;
    static int min = Integer.MAX_VALUE;

    static int[] dx = {0, 1, 0, -1};
    static int[] dy = {1, 0, -1, 0};

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

        StringTokenizer st = new StringTokenizer(br.readLine());
        StringBuilder sb;
        N = Integer.parseInt(st.nextToken());
        M = Integer.parseInt(st.nextToken());
        K = Integer.parseInt(st.nextToken());

        board = new int[N][M];
        visit = new boolean[N][M][K + 1];

        for (int i = 0; i < N; i++) {
            sb = new StringBuilder(br.readLine());
            for(int j=0; j<M; j++){
                board[i][j] = sb.charAt(j)-'0';
            }
        }

        BFS(0,0);

        if (min == Integer.MAX_VALUE) {
            bw.write("-1");
        }else{
            bw.write(String.valueOf(min));
        }
        bw.flush();
        bw.close();

    }

    public static void BFS(int xpos, int ypos) {
        Queue<Main> q = new LinkedList<>();
        q.add(new Main(xpos, ypos, 1, 0));

        visit[xpos][ypos][0]=true;

        while (!q.isEmpty()) {
            Main m = q.poll();
            int x = m.x;
            int y = m.y;
            int dist = m.dist;
            if(x==N-1 && y == M-1){
                if(min > dist){
                    min =dist;
                }
                return;
            }

            for(int i=0; i<4; i++){
                int nx = x +dx[i];
                int ny = y +dy[i];
                if(nx<N && ny<M && nx>=0 && ny>=0){
                    //벽이 아닐 떄
                    if(board[nx][ny]==0 && !visit[nx][ny][m.wall]){
                        visit[nx][ny][m.wall]=true;
                        q.add(new Main(nx, ny, dist + 1, m.wall));
                    } else {

                        if (m.wall<K && board[nx][ny]==1 && !visit[nx][ny][m.wall+1]) {
                            //벽이 있을 때,
                            visit[nx][ny][m.wall+1]=true;
                            q.add(new Main(nx, ny, dist + 1, m.wall + 1));
                        }
                    }
                }
            }
        }
    }
}