#include <cstdio>
#include <cstring>
#include <algorithm>
#include <utility>
#include <cmath>
#include <vector>
#include <cstdarg>
#include <cstdlib>

#define FOR(i, v) for (int i = 0; i < v; i++)
#define FORD(i, v) for (int i = v - 1; i >= 0; i--)
#define REP(i, v, x) for (int i = v; i <= x; i++)
#define REPD(i, v, x) for (int i = v; i >= x; i--)

#define pb push_back
#define fi first
#define se second
#define mp make_pair

#define MAXB 1000

using namespace std;

typedef long long i64;
typedef unsigned long long u64;

char buf[MAXB];

//fgets(buf, MAXB, stdin);
void read(int n, char *s, ...)
{
  int p = 0, v;
  va_list par;
  va_start(par, s);
  while (n--)
  {
    while (s[p] == ' ') p++;
    v = 0;
    while (isdigit(s[p])) v = v * 10 + s[p++] - '0';
    *(va_arg(par, int*)) = v;
  }
  va_end(par);
}

int r, c, mask;
char s[30];
int b[20];
int b2[20];

#define inf 10000000

int go(int i)
{
  int res = 0;
  b2[1] = b[1];
  b2[2] = b[2];
  FOR(j, c) if (i & (1 << j)) b2[1] ^= 7 << j, b2[2] ^= 1 << (j + 1), res++;
  if (r == 1)
  {
    if (!(b2[1] & mask)) return res;
    return inf;
  }
  REP(j, 2, r)
  {
    b2[j + 1] = b[j + 1];
    FOR(k, c) if (b2[j - 1] & (1 << (k + 1)))
    {
      b2[j] ^= 7 << k;
      b2[j + 1] ^= 1 << (k + 1);
      res++;
    }
    if (j == r)
    {
      if (!(b2[j] & mask)) return res;
      return inf;
    }
  }
}

int main()
{
  while (1)
  {
    scanf("%d %d", &r, &c);
    if (!r && !c) break;
    mask = ((1 << c) - 1) << 1;
    FOR(i, r)
    {
      scanf("%s", s);
      b[i + 1] = 0;
      FOR(j, c) 
      {
        int bt = (s[j] == 'X') ? 1 : 0;
        b[i + 1] |= (1 << (j + 1)) * bt;
      }
    }
    int res = inf;
    FOR(i, 1 << c)
    {
      res = min(res, go(i));
    }
    if (res == inf) printf("Damaged billboard.\n");
    else printf("You have to tap %d tiles.\n", res);
  }
  return 0;
}