import sys
input = sys.stdin.readline

# dinic法

from collections import defaultdict,deque

N,M=map(int,input().split())
MAP=[input().strip() for i in range(N)]

V=N*M+2

EDGE=[defaultdict(int) for i in range(N*M+2)]

for i in range(N):
    for j in range(M):
        if MAP[i][j]=="w":
            for z,w in [(i+1,j),(i-1,j),(i,j+1),(i,j-1)]:
                if 0<=z<N and 0<=w<M and MAP[z][w]=="b":
                    EDGE[i*M+j][z*M+w]=1

start=N*M
goal=N*M+1

for i in range(N):
    for j in range(M):
        if MAP[i][j]=="w":
            EDGE[start][i*M+j]=1
        else:
            EDGE[i*M+j][goal]=1

ANS=0
while True:
    # まずBFSする

    DIS=[-1]*V
    Q=deque([start])
    DIS[start]=0
    EDGE2=[[] for i in range(V)]

    while Q:
        x=Q.popleft()
        for to in EDGE[x]:
            if EDGE[x][to]==0:
                continue
            
            if DIS[to]==-1:
                DIS[to]=DIS[x]+1
                Q.append(to)
                EDGE2[x].append(to)
                
            elif DIS[to]==DIS[x]+1:
                EDGE2[x].append(to)

    if DIS[goal]==-1:
        break

    # BFSしたときのEDGEを使ってDFSする

    MINCOST=[float("inf")]*V
    NOW=start
    ROUTE=[-1]*V
    
    while NOW!=-1: # DFS

        cost=MINCOST[NOW]
        
        if NOW==goal:
            ANS+=cost
            i=goal
            
            while i!=start: # goalからたどり,Routeを使ってEDGEの更新
                j=ROUTE[i]
                if EDGE[j][i]==cost:
                    NOW=j
                    EDGE2[j].pop()
                
                EDGE[j][i]-=cost # 使ったルートをいけなく更新
                MINCOST[j]-=cost                
                EDGE[i][j]+=cost # 逆向きに進めるようにする.
                i=j
            continue

        if EDGE2[NOW]:
            to=EDGE2[NOW][-1]
            ROUTE[to]=NOW
            MINCOST[to]=min(cost,EDGE[NOW][to])
            NOW=to

        else:
            if NOW==start:
                break
            EDGE2[ROUTE[NOW]].pop()
            NOW=ROUTE[NOW]
            

ws=0
bs=0

for i in range(N):
    for j in range(M):
        if MAP[i][j]=="w":
            ws+=1
        elif MAP[i][j]=="b":
            bs+=1

ws-=ANS
bs-=ANS

k=min(ws,bs)

print(ANS*100+k*10+(ws+bs-k*2))