h, w = map(int, input().split())
a = [input() for i in range(h)]
INF = 10**18

dp = [[INF] * w for i in range(h)]
dp[0][0] = 0
for i in range(h):
    for j in range(w):
        for ni, nj in [[i+1, j], [i, j+1]]:
            if not(0 <= ni < h and 0 <= nj < w):
                continue
            if a[ni][nj] == ".":
                dp[ni][nj] = min(dp[ni][nj], dp[i][j] + 1)
            else:
                dp[ni][nj] = min(dp[ni][nj], dp[i][j] + 1 + ni + nj)
print(dp[-1][-1])