#include <bits/stdc++.h>

#define INF 1e9
#define MAX_DIM 500

using namespace std;

typedef pair<int,int> ii;

int n, m, dr[] = {-1,0,1,0}, dc[] = {0,1,0,-1}, dist[MAX_DIM][MAX_DIM];
char grid[MAX_DIM][MAX_DIM + 1];

int main() {
    while(scanf("%d%d",&n,&m) != EOF){
        for(int i = 0; i < n; i++) {
            scanf("%s",grid[i]);
        }
        queue<ii> q;
        fill(&dist[0][0],&dist[0][0] + sizeof(dist) / sizeof(dist[0][0]),INF);
        dist[0][0] = 0;
        q.push(ii(0,0));
        while(!q.empty()) {
            ii cur = q.front(); q.pop();

            // if goal state
            if(cur == ii(n - 1,m - 1)) {
                break;
            }

            /*
            '0','1','2',..
            */
            int cur_val = (int)(grid[cur.first][cur.second] - '0');
            for(int k = 0; k < 4; k++) {
                int new_row = cur.first + dr[k] * cur_val;
                int new_col = cur.second + dc[k] * cur_val;
                if(new_row >= 0 && new_row < n && new_col >= 0 && new_col < m &&
                    dist[new_row][new_col] == INF) {
                    dist[new_row][new_col] = dist[cur.first][cur.second] + 1;
                    q.push(ii(new_row,new_col));
                }
            }
        }
        if(dist[n - 1][m - 1] == INF) {
            printf("-1\n");
        } else {
            printf("%d\n",dist[n - 1][m - 1]);
        }
    }
}