#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> G(H);
    for (int i = 0; i < H; ++i) cin >> G[i];

    const int INF = 1e9;

    vector<vector<int>> O(H + 2, vector<int>(W + 2, INF));
    vector<vector<int>> R(H + 2, vector<int>(W + 2, INF));
    vector<vector<int>> C(H + 2, vector<int>(W + 2, INF));
    vector<vector<int>> X(H + 2, vector<int>(W + 2, INF));

    O[1][1] = 0;

    for (int i = 1; i <= H; ++i) {
        for (int j = 1; j <= W; ++j) {
            if (G[i - 1][j - 1] != '#') {
                if (i > 1) O[i][j] = min(O[i][j], O[i - 1][j]);
                if (j > 1) O[i][j] = min(O[i][j], O[i][j - 1]);
                if (i > 1) O[i][j] = min(O[i][j], R[i - 1][j]);
                if (j > 1) O[i][j] = min(O[i][j], C[i][j - 1]);
            } else {
                O[i][j] = INF;
            }

            if (i < H) {
                R[i][j] = min(R[i][j], O[i][j] + 1);
                if (j > 1) R[i][j] = min(R[i][j], R[i][j - 1]);
                if (j > 1) R[i][j] = min(R[i][j], X[i][j - 1]);
            }

            if (j < W) {
                C[i][j] = min(C[i][j], O[i][j] + 1);
                if (i > 1) C[i][j] = min(C[i][j], C[i - 1][j]);
                if (i > 1) C[i][j] = min(C[i][j], X[i - 1][j]);
            }

            if (i < H && j < W) {
                X[i][j] = min(R[i][j] + 1, C[i][j] + 1);
            }
        }
    }

    if (O[H][W] >= INF) {
        cout << -1 << '\n';
    } else {
        cout << (H + W - 2 + O[H][W]) << '\n';
    }
    return 0;
}