#include <algorithm>
#include <bitset>
#include <cctype>
#include <cerrno>
#include <clocale>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <limits>
#include <list>
#include <map>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <utility>
#include <vector>
#include <cwchar>
#include <cwctype>
#include <stack>
#include <limits.h>
using namespace std;
#define MAXN 510int i,j,n,m;
char mp[MAXN][MAXN];const int dx[4] = {0,0,-1,1};
const int dy[4] = {-1,1,0,0};
const int nx[3][4] = {{0,0,-2,1},{0,0,-1,1},{0,0,-1,2}};
const int ny[3][4] = {{-2,1,0,0},{-1,2,0,0},{-1,1,0,0}};
const int nxt[3][4] = {{1,1,2,2},{0,0,1,1},{2,2,0,0}};struct info
{int x,y;int state;
};
inline bool ok(int x,int y)
{return x >= 1 && x <= n && y >= 1 && y <= m;
}
inline bool check(int x,int y,int state)
{if (!ok(x,y)) return false;if (state == 0 && (mp[x][y] == '#' || mp[x][y] == 'E')) return false;if (state == 1 && (!ok(x,y+1) || mp[x][y] == '#' || mp[x][y+1] == '#')) return false;if (state == 2 && (!ok(x+1,y) || mp[x][y] == '#' || mp[x+1][y] == '#')) return false;return true;
}
inline void bfs()
{int i,j,k,tx,ty,ts;info s,e,cur;queue< info > q;static int dist[MAXN][MAXN][3];while (!q.empty()) q.pop();for (i = 1; i <= n; i++){for (j = 1; j <= m; j++){for (k = 0; k < 3; k++){dist[i][j][k] = -1;}}}for (i = 1; i <= n; i++){for (j = 1; j <= m; j++){if (mp[i][j] == 'X'){s.x = i;s.y = j;s.state = 0;for (k = 0; k < 4; k++){tx = i + dx[k];ty = j + dy[k];if (ok(tx,ty) && mp[tx][ty] == 'X'){s.x = min(i,tx);s.y = min(j,ty);if (k < 2) s.state = 1;else s.state = 2;}}}if (mp[i][j] == 'O'){e.x = i;e.y = j;e.state = 0;        }}}        dist[s.x][s.y][s.state] = 0;q.push(s);while (!q.empty()){cur = q.front();q.pop();for (i = 0; i < 4; i++){tx = cur.x + nx[cur.state][i];ty = cur.y + ny[cur.state][i];ts = nxt[cur.state][i];if (check(tx,ty,ts) && dist[tx][ty][ts] == -1){q.push((info){tx,ty,ts});dist[tx][ty][ts] = dist[cur.x][cur.y][cur.state] + 1;if (tx == e.x && ty == e.y && ts == e.state){printf("%d\n",dist[tx][ty][ts]);return;}}}}printf("Impossible\n");
}int main()
{while (scanf("%d%d",&n,&m) && n && m){getchar(); for (i = 1; i <= n; i++){for (j = 1; j <= m; j++){mp[i][j] = getchar();}        getchar();}        bfs();}return 0;}