#include <bits/stdc++.h>
using namespace std;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

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

    auto id = [&](int i, int j) { return i * W + j; };

    vector<unsigned char> fromS(H * W, 0), toG(H * W, 0);

    // fromS
    for (int i = 0; i < H; i++) {
        for (int j = 0; j < W; j++) {
            if (C[i][j] == '#') continue;
            if (i == 0 && j == 0) {
                fromS[id(i, j)] = 1;
            } else {
                bool ok = false;
                if (i > 0 && fromS[id(i - 1, j)]) ok = true;
                if (j > 0 && fromS[id(i, j - 1)]) ok = true;
                fromS[id(i, j)] = ok;
            }
        }
    }

    // toG
    for (int i = H - 1; i >= 0; i--) {
        for (int j = W - 1; j >= 0; j--) {
            if (C[i][j] == '#') continue;
            if (i == H - 1 && j == W - 1) {
                toG[id(i, j)] = 1;
            } else {
                bool ok = false;
                if (i + 1 < H && toG[id(i + 1, j)]) ok = true;
                if (j + 1 < W && toG[id(i, j + 1)]) ok = true;
                toG[id(i, j)] = ok;
            }
        }
    }

    // 0回使用で最短 H+W-2
    if (fromS[id(H - 1, W - 1)]) {
        cout << H + W - 2 << '\n';
        return 0;
    }

    // 1行挿入で H+W-1 を作れるか
    for (int r = 0; r + 1 < H; r++) {
        vector<unsigned char> suff(W + 1, 0);
        for (int j = W - 1; j >= 0; j--) {
            suff[j] = suff[j + 1] || toG[id(r + 1, j)];
        }

        bool pref = false;
        for (int j = 0; j < W; j++) {
            pref = pref || fromS[id(r, j)];
            if (pref && suff[j]) {
                cout << H + W - 1 << '\n';
                return 0;
            }
        }
    }

    // 1列挿入で H+W-1 を作れるか
    for (int c = 0; c + 1 < W; c++) {
        vector<unsigned char> suff(H + 1, 0);
        for (int i = H - 1; i >= 0; i--) {
            suff[i] = suff[i + 1] || toG[id(i, c + 1)];
        }

        bool pref = false;
        for (int i = 0; i < H; i++) {
            pref = pref || fromS[id(i, c)];
            if (pref && suff[i]) {
                cout << H + W - 1 << '\n';
                return 0;
            }
        }
    }

    // それ以外は 2回使えば必ず H+W
    cout << H + W << '\n';
    return 0;
}