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

using namespace std;

const long long INF = 1e18;

int main() {
    int H, W;
    cin >> H >> W;

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

    vector<vector<long long>> dist(H, vector<long long>(W, INF));
    priority_queue<pair<long long, pair<int, int>>, vector<pair<long long, pair<int, int>>>, greater<pair<long long, 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()) {
        long long 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 = (grid[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] == INF) {
        cout << -1 << endl;
    } else {
        cout << dist[H - 1][W - 1] << endl;
    }

    return 0;
}