#include <iostream>
#include <vector>
#include <string>
#include <queue>

using namespace std;

int main() {
    int H, W;
    if (!(cin >> H >> W)) return 0;

    vector<string> C(H);
    for (int i = 0; i < H; ++i) cin >> C[i];

    vector<vector<int>> dist(H, vector<int>(W, 2e9));
    priority_queue<pair<int, pair<int, int>>, vector<pair<int, pair<int, int>>>, greater<pair<int, pair<int, int>>>> pq;

    dist[0][0] = 0;
    pq.push({0, {0, 0}});

    int dr[] = {0, 0, 1, -1};
    int dc[] = {1, -1, 0, 0};

    while (!pq.empty()) {
        int d = pq.top().first;
        int r = pq.top().second.first;
        int c = pq.top().second.second;
        pq.pop();

        if (d > dist[r][c]) continue;

        for (int i = 0; i < 4; ++i) {
            int nr = r + dr[i];
            int nc = c + dc[i];

            if (nr >= 0 && nr < H && nc >= 0 && nc < W) {
                int cost = (C[nr][nc] == '#') ? 2 : 1;
                if (dist[nr][nc] > d + cost) {
                    dist[nr][nc] = d + cost;
                    pq.push({dist[nr][nc], {nr, nc}});
                }
            }
        }
    }

    if (dist[H - 1][W - 1] == 2e9) cout << -1 << endl;
    else cout << dist[H - 1][W - 1] << endl;

    return 0;
}