#include <bits/stdc++.h>

using namespace std;

ifstream fin("barbar.in");
ofstream fout("barbar.out");

const int di[]={0,0,-1,1},dj[]={-1,1,0,0};
int n,m,a[1001][1001],h[1001][1001],si,sj,fi,fj;

struct dragon{
    int i,j,val;
};

queue<dragon>q;

bool ok(int i,int j){
    if(i<1||j<1||i>n||j>m) return false;
    return true;
}

queue<pair<int,int>>q2;

int main(){
    fin>>n>>m;
    char c;
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            fin>>c;
            if(c=='I'){
                si=i;
                sj=j;
                a[i][j]=-1;
            }else if(c=='*'){
                a[i][j]=-1;
                h[i][j]=-1;
            }else if(c=='O'){
                fi=i;
                fj=j;
            }else if(c=='D'){
                a[i][j]=-1;
                h[i][j]=-1;
                dragon aux;
                aux.i=i;
                aux.j=j;
                aux.val=0;
                q.push(aux);
            }
        }
    }
    int st=1,dr=-1,rez=-1,mij,att=1;
    fout<<rez;
    return 0;
}