1 #include<iostream>
  2 #include<stdio.h>
  3 #include<cstring>
  4 #include<cstdlib>
  5 #include<queue>
  6 using namespace std;
  7 
  8 int n,m;
  9 char a[101][101];
 10 bool dp[101][101][(1<<4)+1];
 11 int map1[4][2]={{1,0},{0,1},{0,-1},{-1,0}};
 12 struct node
 13 {
 14     int x,y;
 15     int state;
 16     int time;
 17 };
 18 queue<node>Q;
 19 
 20 int get(char cc)
 21 {
 22     if(cc==‘B‘ || cc==‘b‘)return 0;
 23     else if(cc==‘Y‘ || cc==‘y‘)return 1;
 24     else if(cc==‘R‘ || cc==‘r‘)return 2;
 25     else return 3;
 26 }
 27 int bfs(int x,int y)
 28 {
 29     int i,x1,y1,state;
 30     struct node t,cur;
 31 
 32     t.x=x;
 33     t.y=y;
 34     t.time=0;
 35     t.state=0;
 36     dp[x][y][0]=true;
 37     Q.push(t);
 38     while(!Q.empty())
 39     {
 40         t=Q.front();
 41         Q.pop();
 42         for(i=0;i<4;i++)
 43         {
 44             x1=t.x+map1[i][0];
 45             y1=t.y+map1[i][1];
 46             if(x1>=0&&x1<n && y1>=0&&y1<m && a[x1][y1]!=‘#‘)
 47             {
 48                 if(a[x1][y1]==‘X‘)
 49                 {
 50                     printf("Escape possible in %d steps.\n",t.time+1);
 51                     return 1;
 52                 }
 53                 if(a[x1][y1]>=‘A‘&&a[x1][y1]<=‘Z‘)
 54                 {
 55                     state=(1<<get(a[x1][y1]));
 56                     if( (t.state&state)==state && dp[x1][y1][t.state]==false)
 57                     {
 58                         dp[x1][y1][t.state]=true;
 59                         cur=t;
 60                         cur.time++;
 61                         cur.x=x1;
 62                         cur.y=y1;
 63                         Q.push(cur);
 64                     }
 65                 }
 66                 else if(a[x1][y1]>=‘a‘&&a[x1][y1]<=‘z‘)
 67                 {
 68                     state=(1<<get(a[x1][y1]));
 69                     cur=t;
 70                     cur.state=(cur.state|state);
 71                     if(dp[x1][y1][cur.state]==false)
 72                     {
 73                         dp[x1][y1][cur.state]=true;
 74                         cur.x=x1;
 75                         cur.y=y1;
 76                         cur.time++;
 77                         Q.push(cur);
 78                     }
 79                 }
 80                 else if(dp[x1][y1][t.state]==false)
 81                 {
 82                     dp[x1][y1][t.state]=true;
 83                     cur.x=x1;
 84                     cur.y=y1;
 85                     cur.state=t.state;
 86                     cur.time=t.time+1;
 87                     Q.push(cur);
 88                 }
 89             }
 90         }
 91     }
 92     return -1;
 93 }
 94 int main()
 95 {
 96     int i,j,x,y,k;
 97     bool cur;
 98     while(scanf("%d%d",&n,&m)>0)
 99     {
100         if(n==0&&m==0)break;
101         memset(dp,false,sizeof(dp));
102         while(!Q.empty())
103         {
104             Q.pop();
105         }
106         for(i=0;i<n;i++)
107             scanf("%s",a[i]);
108         cur=false;
109         for(i=0;i<n;i++)
110         {
111             for(j=0;j<m;j++)
112             {
113                 if(a[i][j]==‘*‘)
114                 {
115                     x=i;
116                     y=j;
117                 }
118                 if(a[i][j]==‘X‘)
119                     cur=true;
120             }
121         }
122         if(cur==false) printf("The poor student is trapped!\n");
123         else
124         {
125             k=bfs(x,y);
126             if(k==-1)printf("The poor student is trapped!\n");
127         }
128     }
129     return 0;
130 }