#include<stdio.h>
#include<iostream>
#define MAX_N 51

int map[MAX_N][MAX_N];
int d[MAX_N][MAX_N][MAX_N*MAX_N];
int N, M;
int ans;
bool loop = false;

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

void f(int x, int y, int cnt)
{
    if (loop) return;

    if (cnt > N*M) {
        loop = true;
        return;
    }

    if (cnt > ans) ans = cnt;

    for (int i = 0; i < 4; i++)
    {
        int nx = x + map[x][y] * dx[i];
        int ny = y + map[x][y] * dy[i];
        if (1 <= nx && nx <= N && 1 <= ny && ny <= M){
            if (d[nx][ny][cnt + 1] == 0 && map[nx][ny] != -1){
                d[nx][ny][cnt + 1] = 1;
                f(nx, ny, cnt + 1);
            }
        }
    }
}

int main(){
    //freopen("input.txt", "r", stdin);
    scanf("%d %d", &N, &M);

    char tmp[55];

    for (int i = 1; i <= N; i++){
        scanf("%s", tmp + 1);
        for (int j = 1; j <= M; j++)
        {
            if (tmp[j] == 'H') map[i][j] = -1;
            else map[i][j] = tmp[j] - '0';
        }
    }

    d[1][1][0] = 1;
    f(1, 1, 0);

    if (loop) printf("-1\n");
    else printf("%d\n", ans + 1);
}