/*
 * "El este inteligent.. pare lent dar nu e lent, pentru ca e inteligent si paseaza foarte bine"
 *                                                                      - Gheorghe Hagi
*/
#include <iostream>
#include <fstream>
#include <queue>

using namespace std;

ifstream f ("barbar.in" );
ofstream g ("barbar.out");

static const int NMax = 1e3 + 5;
static const int INF  = 2e9;

int n, m;
int dp[NMax][NMax], cost[NMax][NMax];
int dx[] = {-1, 0, 1,  0};
int dy[] = { 0, 1, 0, -1};

struct hagi {
    int x, y;
}start, fin;

string A[NMax];
queue < pair<int, int> > q;

bool ok(int x, int y) {
    if(x > 0 && x < n + 1 && y > 0 && y < m + 1 && A[x][y] != '*')    return true;
    return false;
}

void bfs() {
    while(!q.empty()) {
        int l = q.front().first;
        int c = q.front().second;
        for(int dir = 0; dir < 4; ++dir) {
            int newL = l + dx[dir];
            int newC = c + dy[dir];
            if(ok(newL, newC)) {
                if(dp[newL][newC] > dp[l][c] + 1) {
                    dp[newL][newC] = dp[l][c] + 1;
                    q.push(make_pair(newL, newC));
                }
            }
        }
        q.pop();
    }

    cost[start.x][start.y] = dp[start.x][start.y];
    q.push(make_pair(start.x, start.y));

    while(!q.empty()) {
        int l = q.front().first;
        int c = q.front().second;
        for(int dir = 0; dir < 4; ++dir) {
            int newL = l + dx[dir];
            int newC = c + dy[dir];
            if(ok(newL, newC)) {
                if(cost[newL][newC] == -1 || cost[newL][newC] < min(dp[newL][newC], cost[l][c])) {
                    cost[newL][newC] = min(dp[newL][newC], cost[l][c]);
                    q.push(make_pair(newL, newC));
                }
            }
        }
        q.pop();
    }

    g << cost[fin.x][fin.y] << ' ';
}

int main()
{
    f >> n >> m;
    for(int i = 1; i <= n; ++i) {
        f >> A[i];
        A[i] = ' ' + A[i];
        for(int j = 1; j <= m; ++j) {
            dp[i][j] = INF;
            if(A[i][j] == 'I') {
                start.x = i;
                start.y = j;
            } else if(A[i][j] == 'O') {
                fin.x = i;
                fin.y = j;
            } else if(A[i][j] == 'D') {
                q.push(make_pair(i, j));
                dp[i][j] = 0;
            }
            cost[i][j] = -1;
        }
    }

    bfs();
    f.close();
    g.close();
    return 0;
}