#include <bits/stdc++.h>

using namespace std;

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

int n, m, l0, c0, lf, cf;
char a[1003][1003];
int parlit[1003][1003], d[1003][1003], dragoni[1003][1003];
queue< pair<int, int> > q;
int dx[] = {0,0,-1,1};
int dy[] = {-1,1,0,0};

void Citire()
{
    int i, j;
    fin >> n >> m;
    fin.get();
    for(i = 1;i <= n;i++)
        fin >> (a[i] + 1);
}

void Bordare()
{
    int i, j;
    for(i = 0;i <= n + 1;i++)
        a[i][0] = a[i][m + 1] = '*';
    for(j = 0;j <= m + 1;j++)
        a[0][j] = a[n + 1][j] = '*';
}

void Init()
{
    int i, j;
    for(i = 1;i <= n;i++)
        for(j = 1;j <= m;j++)
            d[i][j] = dragoni[i][j] = 2e9;
}

void Arie_Dragoni
{
    int i, j, x, y, k;
    for(i = 1;i <= n;i++)
        for(j = 1;j <= m;j++)
            if(a[i][j] == 'D')
            {
                q.push({i, j});
                dragoni[i][j] = 0;
            }
            else if(a[i][j] == 'I')
            {
                l0 = i;
                c0 = j;
            }
            else if(a[i][j] == 'O')
            {
                lf = i;
                cf = j;
            }
    while(!q.empty())
    {
        i = q.front().first;
        j = q.front().second;
        q.pop();
        for(k = 0;k < 4;k++)
        {
            x = i + dx[k];
            y = j + dy[k];
            if(dragoni[x][y] > dragoni[i][j] + 1)
            {
                dragoni[x][y] = dragoni[i][j] + 1;
                q.push({x,y});
            }
        }
    }
}

void Lee()
{
    int i, j, x, y, k;
    q.push({l0, c0});

}

int main()
{
    Citire();
    Bordare();
    Init();
    Arie_Dragoni();
}