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

dist = [[10**13]*(W+1) for _ in range(H+1)]
dist[1][1] = 0
for i in range(H):
    for j in range(W):
        if i == 0 and j == 0:
            continue
        if L[i][j] == ".":
            dist[i+1][j+1] = min(dist[i][j+1], dist[i+1][j]) + 1
        else:
            dist[i+1][j+1] = min(dist[i][j+1], dist[i+1][j]) + (i+j+1)

print(dist[H][W])