#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/hash_policy.hpp>
#define Add(x, y) (x + y >= mod) ? (x + y - mod) : (x + y)
#define lowbit(x) x & (-x)
#define pi pair<ll, ll>
#define pii pair<ll, pair<ll, ll>>
#define iip pair<pair<ll, ll>, ll>
#define ppii pair<pair<ll, ll>, pair<ll, ll>>
#define ls(k) k << 1
#define rs(k) k << 1 | 1
#define fi first
#define se second
#define full(l, r, x) for(auto it = l; it != r; ++it) (*it) = x
#define Full(a) memset(a, 0, sizeof(a))
#define open(s1, s2) freopen(s1, "r", stdin), freopen(s2, "w", stdout);
#define For(i, l, r) for(register int i = l; i <= r; ++i)
#define _For(i, l, r) for(register int i = r; i >= l; --i)
using namespace std;
using namespace __gnu_pbds;
typedef double db;
typedef unsigned long long ull;
typedef long long ll;
bool Begin;
const int N = 51, M = N * N;
inline ll read(){
    ll x = 0, f = 1;
    char c = getchar();
    while(c < '0' || c > '9'){
        if(c == '-')
          f = -1;
        c = getchar();
    }
    while(c >= '0' && c <= '9'){
        x = (x << 1) + (x << 3) + (c ^ 48);
        c = getchar();
    }
    return x * f;
}
inline void write(ll x){
	if(x < 0){
		putchar('-');
		x = -x;
	}
	if(x > 9)
	  write(x / 10);
	putchar(x % 10 + '0');
}
int n, m, s1, s2, ans;
int id[N][N];
int a[M];
bool f[M];
char s[N][N];
int dx[] = {0, 0, 1, - 1}, dy[] = {1, -1, 0, 0};
vector<int> E[M];
inline void add(int u, int v){
	E[u].push_back(v);
}
inline bool dfs(int u){
	for(auto v : E[u]){
		if(f[v])
		  continue;
		f[v] = 1;
		if(!a[v] || dfs(a[v])){
			a[v] = u;
			return 1;
		}
	}
	return 0;
}
inline void Match(){
	for(int i = 1; i <= n * m; ++i){
		for(int j = 1; j <= n * m; ++j)
		  f[j] = 0;
		if(dfs(i))
		  ans++;
	}
}
bool End;
int main(){
	n = read(), m = read();
	for(int i = 1; i <= n; ++i){
		scanf("%s", s[i] + 1);
		for(int j = 1; j <= m; ++j)
		  id[i][j] = (i - 1) * m + j;
	}
	for(int i = 1; i <= n; ++i){
		for(int j = 1; j <= m; ++j){
			s1 += (s[i][j] == 'w'), s2 += (s[i][j] == 'b');
			if(s[i][j] != 'w')
			  continue;
			for(int k = 0; k < 4; ++k){
				int zx = i + dx[k], zy = j + dy[k];
				if(zx < 1 || zx > n || zy < 1 || zy > m)
				  continue;
				if(s[zx][zy] != 'b')
				  continue;
				add(id[i][j], id[zx][zy]);
			}
		}
	} 
	Match();
	s1 -= ans, s2 -= ans;
	write(ans * 100 + min(s1, s2) * 10 + max(s1, s2) - min(s1, s2));
	cerr << '\n' << abs(&Begin - &End) / 1048576 << "MB";
	return 0;
}