#include<cstdio>

#include<cstring>

#include<algorithm>

#include<queue>

using namespace std;

int dx[]={0,-1,0,1},dy[]={-1,0,1,0};

#define INF 2147483647

#define MAXN 1605

#define MAXM 12805

int v[MAXM],cap[MAXM],en,first[MAXN],next[MAXM];

int d[MAXN],cur[MAXN];

queue<int>q;

int S,T;

void Init_Dinic(){memset(first,-1,sizeof(first)); en=0;}

void AddEdge(const int &U,const int &V,const int &W)

{

    v[en]=V; cap[en]=W;

    next[en]=first[U]; first[U]=en++;

    v[en]=U; cap[en]=0;

    next[en]=first[V]; first[V]=en++;

}

bool bfs()

{

    memset(d,-1,sizeof(d)); q.push(S); d[S]=0;

    while(!q.empty())

      {

          int U=q.front(); q.pop();

          for(int i=first[U];i!=-1;i=next[i])

            if(d[v[i]]==-1 && cap[i])

              {

                d[v[i]]=d[U]+1;

                q.push(v[i]);

              }

      }

    return d[T]!=-1;

}

int dfs(int U,int a)

{

    if(U==T || !a) return a;

    int Flow=0,f;

    for(int &i=cur[U];i!=-1;i=next[i])

      if(d[U]+1==d[v[i]] && (f=dfs(v[i],min(a,cap[i]))))

        {

          cap[i]-=f; cap[i^1]+=f;

          Flow+=f; a-=f; if(!a) break;

        }

    if(!Flow) d[U]=-1;

    return Flow;

}

int max_flow()

{

    int Flow=0,tmp=0;

    while(bfs())

      {

          memcpy(cur,first,sizeof(first));

          while(tmp=dfs(S,INF)) Flow+=tmp;

      }

    return Flow;

}

int n,m,num[45][45],p;

char a[45][45];

bool b[45][45],pen=1;

bool vis[45][45];

void df2(int x,int y){

	vis[x][y]=1;

	for(int i=0;i<4;++i){

		int tx=x+dx[i],ty=y+dy[i];

		if(a[tx][ty]=='L' && !vis[tx][ty]){

			df2(tx,ty);

		}

	}

}

int main(){

//	freopen("g.in","r",stdin);

	scanf("%d%d",&n,&m);

	for(int i=1;i<=n;++i){

		scanf("%s",a[i]+1);

	}

	int cnt=0;

	for(int i=1;i<=n;++i){

		for(int j=1;j<=m;++j){

			if(!vis[i][j] && a[i][j]=='L'){

				++cnt;

				df2(i,j);

			}

		}

	}

	for(int i=1;i<=n;++i){

		for(int j=1;j<=m;++j){

			if(a[i][j]=='L'){

				for(int k=0;k<4;++k){

					int tx=i+dx[k],ty=j+dy[k];

					if(a[tx][ty]=='C'){

						a[tx][ty]='W';

					}

				}

			}

			num[i][j]=++p;

		}

	}

	for(int i=1;i<=n;++i){

		if(i&1){

			for(int j=1;j<=m;++j){

				b[i][j]=pen;

				pen^=1;

			}

		}

		else{

			for(int j=m;j>=1;--j){

				b[i][j]=pen;

				pen^=1;

			}

		}

	}

	S=n*m+1;

	T=S+1;

	Init_Dinic();

	for(int i=1;i<=n;++i){

		for(int j=1;j<=m;++j){

			if(a[i][j]=='C'){

				++cnt;

				if(b[i][j]){

					AddEdge(S,num[i][j],1);

					for(int k=0;k<4;++k){

						int tx=i+dx[k],ty=j+dy[k];

						if(a[tx][ty]=='C' && !b[tx][ty]){

							AddEdge(num[i][j],num[tx][ty],INF);

						}

					}

				}

				else{

					AddEdge(num[i][j],T,1);

				}

			}

		}

	}

	printf("%d\n",cnt-max_flow());

	return 0;

}