import sys
input = sys.stdin.readline

H,W=map(int,input().split())
S=[list(input().strip()) for i in range(H)]

OK=[[0]*W for i in range(H)]
OK[2][2]=1
Q=[(2,2)]

while Q:
    x,y=Q.pop()

    for z,w in [(x+1,y),(x-1,y),(x,y+1),(x,y-1)]:
        if 2<=z<H and 2<=w<W and OK[z][w]==0:

            flag=1

            for x0 in range(3):
                for y0 in range(3):
                    if S[z-x0][w-y0]=="#":
                        flag=0
                        break

            if flag==1:
                OK[z][w]=1
                Q.append((z,w))

if OK[H-1][W-1]==0:
    print(0)
    exit()

for i in range(H):
    for j in range(W):
        if i<=2 and j<=2 :
            continue
        if i>=H-3 and j>=W-3:
            continue
        if S[i][j]=="#":
            continue
    
        S[i][j]="#"

        OK=[[0]*W for i in range(H)]
        OK[2][2]=1
        Q=[(2,2)]

        while Q:
            x,y=Q.pop()

            for z,w in [(x+1,y),(x-1,y),(x,y+1),(x,y-1)]:
                if 2<=z<H and 2<=w<W and OK[z][w]==0:

                    flag=1

                    for x0 in range(3):
                        for y0 in range(3):
                            if S[z-x0][w-y0]=="#":
                                flag=0
                                break

                    if flag==1:
                        OK[z][w]=1
                        Q.append((z,w))

        if OK[H-1][W-1]==0:
            print(1)
            exit()

        S[i][j]="."

print(2)