TSP 也就是 Hamilton Path 的最小成本
//
// GGGGGGGGGGGGG CCCCCCCCCCCCC AAA
// GGG::::::::::::G CCC::::::::::::C A:::A
// GG:::::::::::::::G CC:::::::::::::::C A:::::A
// G:::::GGGGGGGG::::G C:::::CCCCCCCC::::C A:::::::A
// G:::::G GGGGGG C:::::C CCCCCC A:::::::::A
//G:::::G C:::::C A:::::A:::::A
//G:::::G C:::::C A:::::A A:::::A
//G:::::G GGGGGGGGGGC:::::C A:::::A A:::::A
//G:::::G G::::::::GC:::::C A:::::A A:::::A
//G:::::G GGGGG::::GC:::::C A:::::AAAAAAAAA:::::A
//G:::::G G::::GC:::::C A:::::::::::::::::::::A
// G:::::G G::::G C:::::C CCCCCC A:::::AAAAAAAAAAAAA:::::A
// G:::::GGGGGGGG::::G C:::::CCCCCCCC::::C A:::::A A:::::A
// GG:::::::::::::::G CC:::::::::::::::C A:::::A A:::::A
// GGG::::::GGG:::G CCC::::::::::::C A:::::A A:::::A
// GGGGGG GGGG CCCCCCCCCCCCCAAAAAAA AAAAAAA
#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <climits>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <cctype>
#include <utility>
#include <ctime>
using namespace std;
#ifdef DEBUG
#define VAR(a,b) decltype(b) a=(b)
#define debug(...) printf("DEBUG: "),printf(__VA_ARGS__)
#define gettime() end_time=clock();printf("now running time is %.7f\\n",(float)(end_time - start_time)/CLOCKS_PER_SEC);
#else
#define VAR(a,b) __typeof(b) a=(b)
#define debug(...)
#define gettime()
#endif
typedef unsigned int uint;
typedef long long int Int;
typedef unsigned long long int UInt;
#define Set(a,s) memset(a,s,sizeof(a))
#define Write(w) freopen(w,"w",stdout)
#define Read(r) freopen(r,"r",stdin)
#define Pln() printf("\\n")
#define I_de(x,n)for(int i=0;i<n;i++)printf("%d ",x[i]);Pln()
#define De(x)printf(#x"%d\\n",x)
#define For(i,x)for(int i=0;i<x;i++)
#define CON(x,y) x##y
#define Pmz(dp,nx,ny)for(int hty=0;hty<ny;hty++){for(int htx=0;htx<nx;htx++){\\
printf("%d ",dp[htx][hty]);}Pln();}
#define M 30
#define PII pair<int,int>
#define PB push_back
#define oo INT_MAX
#define Set_oo 0x3f
#define FOR(a,b) for(VAR(a,(b).begin());a!=(b).end();++a)
#define eps 1e-6
#define X first
#define Y second
clock_t start_time=clock(), end_time;
bool xdy(double x,double y){return x>y+eps;}
bool xddy(double x,double y){return x>y-eps;}
bool xcy(double x,double y){return x<y-eps;}
bool xcdy(double x,double y){return x<y+eps;}
int min3(int x,int y,int z){
int tmp=min(x,y);
return min(tmp,z);
}
int max3(int x,int y,int z){
int tmp=max(x,y);
return max(tmp,z);
}
int nx,ny;
int nuts;
int nutx[M],nuty[M];
char str[M];
int mz[M][M];
int dp[1<<18][18];
int dfs(int state,int x){
if(dp[state][x]!=-1)return dp[state][x];
if(state==(1<<(nuts))-1){
return dp[state][x]=mz[x][0];
}
int minans=oo;
for(int i=1;i<nuts;i++){
if(!((state>>i)&1)&&i!=x){
int h=dfs(state|(1<<i),i);
if(h){
minans=min(minans,mz[x][i]+h);
}
}
}
if(minans==oo){
minans=0;
}
return dp[state][x]=minans;
}
void solve(){
Set(mz,-1);
Set(dp,-1);
for(int i=0;i<nuts;i++){
for(int j=i;j<nuts;j++){
mz[i][j]=mz[j][i]=max(abs(nutx[i]-nutx[j]),abs(nuty[i]-nuty[j]));
}
}
printf("%d\\n",dfs(1,0));
}
int main() {
ios_base::sync_with_stdio(0);
while(~scanf("%d%d",&ny,&nx)){
nuts=1;
for(int i=0;i<ny;i++){
scanf("%s",str);
for(int j=0;j<nx;j++){
if(str[j]=='L')nutx[0]=j,nuty[0]=i;
if(str[j]=='#')nutx[nuts]=j,nuty[nuts++]=i;
}
}
solve();
}
}