#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 long long INF = (long long)4e18;

    vector<long long> upA(w, INF), upB(max(0, w - 1), INF), upC(w, INF), upD(max(0, w - 1), INF);

    for (int r = 0; r < h; r++) {
        vector<long long> a(w, INF), b(max(0, w - 1), 0), c(w, 0), d(max(0, w - 1), 0);

        long long leftA = INF, leftB = INF, leftC = INF, leftD = INF;
        bool down = (r + 1 < h);
        bool top = (r > 0);
        bool first = (r == 0);

        for (int j = 0; j < w; j++) {
            long long cur = (first && j == 0 ? 0 : INF);

            if (g[r][j] != '#') {
                if (upA[j] < cur) cur = upA[j];
                if (upC[j] < cur) cur = upC[j];
                if (leftA < cur) cur = leftA;
                if (leftB < cur) cur = leftB;
            }

            a[j] = cur;

            long long x = 0, y = 0;

            if (j + 1 < w) {
                x = cur + 1;
                if (top) {
                    if (upB[j] < x) x = upB[j];
                    if (upD[j] < x) x = upD[j];
                }
                b[j] = x;
            }

            if (down) {
                y = cur + 1;
                if (j) {
                    if (leftC < y) y = leftC;
                    if (leftD < y) y = leftD;
                }
                c[j] = y;
            }

            if (down && j + 1 < w) {
                long long z = x;
                if (y < z) z = y;
                d[j] = z + 1;
            }

            leftA = cur;
            if (j + 1 < w) leftB = b[j];
            if (down) {
                leftC = c[j];
                if (j + 1 < w) leftD = d[j];
            }
        }

        upA.swap(a);
        upB.swap(b);
        upC.swap(c);
        upD.swap(d);
    }

    long long res = upA[w - 1];
    if (res >= INF / 2) cout << -1 << '\n';
    else cout << res + h + w - 2 << '\n';

    return 0;
}