#include<bits/stdc++.h>
using namespace std;
int n,S,T;
int hd[100005],nxt[800005],c[800005],dy[800005],tot=1;
int cur[100005],l[100005];
void addedge(int u,int v,int w){
    nxt[++tot]=hd[u],hd[u]=tot;
    c[tot]=w,dy[tot]=v;
}
bool getc(){
    for(int i=1;i<=n;++i)l[i]=1e9,cur[i]=hd[i];
    l[S]=0;
    queue<int>q;
    q.emplace(S);
    while(q.size()){
        int x=q.front();
        q.pop();
        for(int i=hd[x];i;i=nxt[i]){
            if(!c[i])continue;
            int cu=dy[i];
            if(l[cu]>l[x]+1){
                l[cu]=l[x]+1;
                q.emplace(cu);
            }
        }
    }
    return l[T]<1e9;
}
int ans=0;
int dinic(int x,int rl){
    if(x==T){
        ans+=rl;
        return rl;
    }
    int rr=rl;
    for(int i=cur[x];i;i=nxt[i]){
        cur[x]=i;
        if(!c[i])continue;
        int cu=dy[i];
        if(l[cu]!=l[x]+1)continue;
        int zz=dinic(cu,min(rr,c[i]));
        c[i]-=zz,c[i^1]+=zz;
        rr-=zz;
        if(!rr)break;
    }
    return rl-rr;
}
char s[105][105];
#define mk(x,y) (((x)-1)*M+(y))
int mb[4][2]={{0,1},{1,0},{0,-1},{-1,0}};
int main(){
	int N,M;
	scanf("%d%d",&N,&M);
	n=N*M+2,S=n-1,T=n;
	int bb=0,ww=0;
	for(int i=1;i<=N;++i){
		scanf("%s",s[i]+1);
		for(int j=1;j<=M;++j)if(s[i][j]!='.'){
			if(s[i][j]=='w')addedge(S,mk(i,j),1),addedge(mk(i,j),S,0),++ww;
			else addedge(mk(i,j),T,1),addedge(T,mk(i,j),0),++bb;
		}
	}
	for(int i=1;i<=N;++i)for(int j=1;j<=M;++j)if(s[i][j]=='w'){
		for(int k=0;k<4;++k){
			int dx=i+mb[k][0],dy=j+mb[k][1];
			if(dx<1||dx>N||dy<1||dy>M||s[dx][dy]!='b')continue;
			addedge(mk(i,j),mk(dx,dy),1);
			addedge(mk(dx,dy),mk(i,j),0);
		}
	}
	while(getc())dinic(S,INT_MAX);
	int an=bb+ww+8*min(bb,ww)+90*ans;
	printf("%d\n",an);
    return 0;
}