1 #include <iostream>
 2 #include <cstdlib>
 3 #include <cstdio>
 4 #include <algorithm>
 5 #define INF 0x3f3f3f3f
 6 using namespace std;
 7 int n, dis[20][20], myX, myY, f[20][(1 << 20)];
 8
 9 struct myNode {
10     int x, y;
11 }node[20];
12
13 void Init(int i, char str[])
14 {
15     for (int j = 0; j < myY; ++j){
16         if ('#' == str[j]) {
17             node[++n].x = i;
18             node[n].y = j;
19         }
20         else if ('L' == str[j]) {
21             node[0].x = i;
22             node[0].y = j;
23         }
24     }
25 }
26
27 void getDis() {
28     for (int i = 0; i <= n; ++i) {
29         for (int j = 0; j <= n; ++j) {
30             dis[i][j] = max(abs(node[i].x - node[j].x), abs(node[i].y - node[j].y));
31         }
32     }
33 }
34
35 void Solve() {
36     int finalState = (1 << n) - 1;
37     for (int j = 1; j <= n; ++j) {
38         for (int i = 0; i <= finalState; ++i) {
39             f[j][i] = INF;
40         }
41     }
42     for (int j = 1; j <= n; ++j) {
43         f[j][1 << (j - 1)] = dis[0][j];
44     }
45     for (int i = 0; i < finalState; ++i) {
46         for (int j = 1; j <= n; ++j) {
47             if (i & (1 << (j - 1))) {
48                 for (int k = 1; k <= n; ++k) {
49                     if (!(i & (1 << (k - 1)))) {
50                         f[k][i + (1 << (k - 1))] = min(f[k][i + (1 << (k - 1))], f[j][i] + dis[j][k]);
51                     }
52                 }
53             }
54         }
55     }
56     int ans = INF;
57     for (int j = 1; j <= n; ++j) {
58         ans = min(ans, f[j][finalState] + dis[j][0]);
59     }
60     printf("%d\n", ans);
61 }
62
63 int main()
64 {
65     while (~scanf("%d %d", &myX, &myY)) {
66         char str[25];
67         n = 0;
68         for (int i = 0; i < myX; ++i) {
69             scanf("%s", str);
70             Init(i, str);
71         }
72         if (0 == n) {   // 注意无坚果的情况。。
73             printf("0\n");
74             continue;
75         }
76         getDis();
77         Solve();
78     }
79     return 0;
80 }