import sys
input = sys.stdin.readline
sys.setrecursionlimit(10 ** 7)
inf = 10**9

H, W = map(int, input().split())
G = [input().rstrip() for _ in range(H)]

dp = [[inf] * W for _ in range(H)]
dp[0][0] = 0
for i in range(H):
    for j in range(W):
        if G[i][j] == ".":
            if i:
                dp[i][j] = min(dp[i][j], dp[i-1][j] + 1)
            if j:
                dp[i][j] = min(dp[i][j], dp[i][j-1] + 1)
        else:
            if i:
                dp[i][j] = min(dp[i][j], dp[i-1][j] + i + j + 1)
            if j:
                dp[i][j] = min(dp[i][j], dp[i][j-1] + i + j + 1)

print(dp[H-1][W-1])