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#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int inf = 0x3f3f3f3f;
const int N = 100 + 10;
int n, m, sx, sy, ex, ey, minn = inf;
char s[N][N];
int vis[N][N][(1 << 10) + 10];
int go[4][2] = {1, 0, -1, 0, 0, 1, 0, -1};
struct node
{
    int x, y, step, key;
    node() {}
    node(int _x, int _y, int _step, int _key)
    {
        x = _x, y = _y, step = _step, key = _key;
    }
};
int pd(int x, int y)
{
    if (x >= 1 && x <= n && y >= 1 && y <= m)
        return 1;
    return 0;
}
int bfs()
{
    node now(sx, sy, 0, 0), to;
    vis[sx][sy][0] = 1;
    queue<node> q;
    q.push(now);
    while (!q.empty())
    {
        now = q.front();
        q.pop();
        if (now.x == ex && now.y == ey)
            return now.step;
        for (int i = 0; i < 4; i++)
        {
            to.x = now.x + go[i][0];
            to.y = now.y + go[i][1];
            to.step = now.step + 1;
            to.key = now.key;
            if (pd(to.x, to.y) && s[to.x][to.y] != '0' && !vis[to.x][to.y][to.key])
            {
                if (s[to.x][to.y] >= 'A' && s[to.x][to.y] <= 'Z')
                {
                    int key = to.key | (1 << (s[to.x][to.y] - 'A'));
                    if (key != to.key)
                        continue;
                }
                if (s[to.x][to.y] >= 'a' && s[to.x][to.y] <= 'z')
                {
                    to.key |= (1 << (s[to.x][to.y] - 'a'));
                }
                vis[to.x][to.y][to.key] = 1;
                q.push(to);
            }
        }
    }
    return 0;
}
int main()
{
    //freopen("in.txt", "r", stdin);
    scanf("%d%d", &n, &m);
    for (int i = 1; i <= n; i++)
    {
        scanf("%s", s[i] + 1);
        for (int j = 1; j <= m; j++)
        {
            if (s[i][j] == '2')
                sx = i, sy = j;
            if (s[i][j] == '3')
                ex = i, ey = j;
        }
    }
    printf("%d\n", bfs());
    return 0;
}