#include <cstdio>
#include <vector>

using namespace std;

int main()
{
	vector<unsigned int> bsz(1<<16,-1);
	bsz[0]=0;
	for(unsigned int i=1;i<(1<<16);++i)
	{
		bsz[i]=bsz[i>>1]+(i&1);
	}
  unsigned int r, c;
  char sor[20];
  while(scanf("%d %d", &r, &c), r+c)
  {
    vector<unsigned int> t(c,0);
    for(unsigned int j=0;j<r;++j)
    {
      scanf("%s", sor);
      for(unsigned int i=0;i<c;++i)
      {
        t[j]<<=1;
        if(sor[i]=='X')
          t[j]|=1;
      }
    }
    unsigned int h=1<<c;
		unsigned int m=~((~0)<<c);
		unsigned int min=257;

		for(unsigned int i=0;i<h;++i)
		{
			unsigned int w=i;
			unsigned int p=0, tp;
			unsigned int cur=0;
			for(unsigned int j=0;j<r;++j)
			{
				cur+=bsz[w];
				tp=w;
				w=(t[j] ^ p ^ w ^ (w>>1) ^ ((w<<1) & m));
			  p=tp;
			}
			if(w==0)
			{
				if(cur<min) min=cur;
			}
		}
		if(min==257)
		{
			printf("Damaged billboard.\n");
		}
		else {
			printf("You have to tap %d tiles.\n", min);
		}
  }
  return 0;
}