import sys
input = sys.stdin.readline

H, W = map(int, input().split())
a = [input()[:-1] for _ in range(H)]
dp = [[10**18]*W for _ in range(H)]
dp[0][0] = 0

for i in range(H):
    for j in range(W):
        if i>0:
            dp[i][j] = min(dp[i][j], dp[i-1][j]+(1 if a[i][j]=='.' else i+j+1))
            
        if j>0:
            dp[i][j] = min(dp[i][j], dp[i][j-1]+(1 if a[i][j]=='.' else i+j+1))
    
print(dp[H-1][W-1])