#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<algorithm>
#include<cassert>
#include<utility>
#include<queue>
#include<stack>
#include<vector>
#include<map>
#include<set>
#include<bitset>

#define rep(i,l,r) for(int i=(l);i<=(r);i++)
#define per(i,r,l) for(int i=(r);i>=(l);i--)

#define all(vc) vc.begin(),vc.end()
#define sz(vc) ((int)vc.size())
#define pb push_back
#define fi first
#define se second
#define x0 __x00
#define y0 __y00

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

const int N=55,M=2505;
int n,m,mt[M];
char ch[N][N];
bool st[M];
vector<int>G[M];
int get(int x,int y){
    return (x-1)*m+y;
}
void add(int a,int b,int c,int d){
    G[get(a,b)].pb(get(c,d));
    G[get(c,d)].pb(get(a,b));
}
bool dfs(int x){
    st[x]=1;
    for(auto to:G[x]){
        int _=mt[to];
        if(_<0||(!st[_]&&dfs(_))){
            mt[x]=to,mt[to]=x;
            return 1;
        }
    }return 0;
}


int main(){


    ios::sync_with_stdio(0);
    cin.tie(0),cout.tie(0);
   

    cin>>n>>m;
    rep(i,1,n)rep(j,1,m)cin>>ch[i][j];
    int b,w;b=w=0;
    rep(i,1,n)rep(j,1,m){
        if(ch[i][j]=='.')continue;
        b+=ch[i][j]=='b';
        w+=ch[i][j]=='w';
        if(i<n&&ch[i+1][j]!='.')add(i,j,i+1,j);
        if(j<m&&ch[i][j+1]!='.')add(i,j,i,j+1);
    }
    memset(mt,-1,sizeof(mt));
    int res=0;
    rep(i,1,n*m)
        if(mt[i]<0)memset(st,0,sizeof(st)),res+=dfs(i);

    b-=res,w-=res;
    cout<<res*100ll+min(b,w)*10+abs(b-w)<<'\n';


    return 0;
}