#include<algorithm> #include<iostream> #include<cstring> #include<cstdlib> #include<cstdio> #define inf 0x7fffffff using namespace std; inline int read(){ int x=0,f=1;char ch=getchar(); while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();} while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();} return x*f; } struct edge{int from,to,next,v,c;}e[200001]; int mp[16][16],mark[16][16],xx[4]={0,0,-1,1},yy[4]={-1,1,0,0}; int n,m,cnt=1,ans,T=2001,head[2005],from[2005],dis[2005]; inline void ins(int u,int v,int w,int c){ e[++cnt]=(edge){u,v,head[u],w,c};head[u]=cnt; e[++cnt]=(edge){v,u,head[v],0,-c};head[v]=cnt; } inline bool spfa(){ int t=0,w=1,q[10001]; bool inq[10001]; memset(inq,0,sizeof(inq)); for(int i=0;i<=T;i++)dis[i]=inf; dis[0]=0;q[0]=0;inq[0]=1; while(t!=w){ int now=q[t++];if(t==T)t=0; for(int i=head[now];i;i=e[i].next) if(e[i].v&&dis[e[i].to]>dis[now]+e[i].c){ dis[e[i].to]=dis[now]+e[i].c; from[e[i].to]=i; if(!inq[e[i].to]){ inq[e[i].to]=1; q[w++]=e[i].to; if(w==T)w=0; } } inq[now]=0; } if(dis[T]==inf)return 0; return 1; } inline void mcf(){ int x=inf; for(int i=from[T];i;i=from[e[i].from])x=min(x,e[i].v); for(int i=from[T];i;i=from[e[i].from]){ e[i].v-=x;e[i^1].v+=x;ans+=e[i].c*x; } } int main(){ n=read();m=read(); for(int i=1;i<=n;i++) for(int j=1;j<=m;j++) mark[i][j]=(i-1)*m+j; for(int i=1;i<=n;i++){ char ch[21];scanf("%s",ch); for(int j=1;j<=m;j++){ if(ch[j-1]=='L')mp[i][j]=0; if(ch[j-1]=='R')mp[i][j]=1; if(ch[j-1]=='U')mp[i][j]=2; if(ch[j-1]=='D')mp[i][j]=3; } } for(int i=1;i<=n;i++) for(int j=1;j<=m;j++) for(int k=0;k<4;k++){ int nowx=i+xx[k],nowy=j+yy[k]; if(nowx>n)nowx=1;if(nowx<1)nowx=n; if(nowy>m)nowy=1;if(nowy<1)nowy=m; if(k==mp[i][j])ins(mark[i][j],mark[nowx][nowy]+300,1,0); else ins(mark[i][j],mark[nowx][nowy]+300,1,1); } for(int i=1;i<=n*m;i++){ins(0,i,1,0);ins(i+300,T,1,0);} while(spfa())mcf(); printf("%d",ans); return 0; }