#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<climits>
#include<cmath>
#include<algorithm>

using namespace std;

#define PRINTF(args...) printf(args)
//#define PRINTF(args...) 

#define FOR(i,a,b) for(int i=(a); i<(int)(b); ++i)
#define FORD(i,a,b) for(int i=(a)-1; i>=(int)(b); --i)
#define FOREACH(i,C) for(__typeof(C.begin()) i=C.begin(); i!=C.end(); ++i)

const int nMax = 17;

char tab[nMax][nMax];
char tabA[nMax][nMax];
int n,m;

const int INF = 1000000000;

void change(int x, int y) {
	FOR(i,-1,2) FOR(j,-1,2) if(abs(i)+abs(j)<2 && x+i<n && x+i>=0 && y+j<m && y+j>=0)
		tab[x+i][y+j] = 1-tab[x+i][y+j];
}

bool testcase() {

	scanf("%d %d",&n,&m);
	if(n==0 && m==0)
		return false;
		
	FOR(i,0,n)
		scanf("%s",tabA[i]);
		
	if(m>n) {
		FOR(i,0,n) FOR(j,0,m)
			tab[j][i] = tabA[i][j];
		swap(n,m);
		FOR(i,0,n) FOR(j,0,m)
			tabA[i][j] = tab[i][j];
	}
		
	int best = INF;
	
	FOR(mask,0,(1<<m)) {
		FOR(i,0,n) FOR(j,0,m) if(tabA[i][j]=='.')
			tab[i][j] = 0; else
			tab[i][j] = 1;
		int res = 0;
		FOR(i,0,m) if((1<<i)&mask) {
			change(0,i);
			res++;
		}
		FOR(i,0,(n-1)) FOR(j,0,m) if(tab[i][j]) {
			res++;
			change(i+1,j);
		}
		bool isOk = true;
		FOR(i,0,m) if(tab[n-1][i]==1)
			isOk = false;
		if(isOk)
			best <?= res;
	}
	
	if(best==INF)
		printf("Damaged billboard.\n"); else
		printf("You have to tap %d tiles.\n",best);

	return true;
}

int main() {
	while(testcase());
	return 0;
}