#include <stdio.h>

#define COORD(x,y) ((x)*C + (y))
#define BC(x,y) ((x)*16 + (y))
#define XOREGY(A,B) (A) = (A) ? !(B) : (B)

bool def_coeffs[256][256];
bool **coeffs = new bool*[256];

int C, R;
int RC;

bool variables[256];
bool rights[256];

bool solve()
{
/*	for (int i = 0; i < RC; i++) {
		for (int j = 0; j < RC; j++) {
			printf("%d ", coeffs[i][j]);
		}
		printf("\n");
	}
	printf(" *** \n");*/
	
	int x,y,z; int xs;
	
	xs = 0;
	for (x=0; x<RC; x++)
	{
		/*
		for (int i = 0; i < RC; i++) {
			for (int j = 0; j < RC; j++) {
				printf("%d ", coeffs[i][j]);
			}
			printf("\n");
		}
		printf(" *** \n");
	*/
		for (y=xs; (y<RC) && !coeffs[y][x]; ++y);
		
		if (y >= RC) 
		{
			
		}
		 else {
			 
			if (y!=xs)
			{
				bool tmp2 = rights[xs];
				rights[xs] = rights[y];
				rights[y] = tmp2;
				
				/*bool* tmp1 = coeffs[x];
				coeffs[x] = coeffs[y];
				coeffs[y] = tmp1;*/
				
				bool tmp1;
				for (int i = 0; i < 256; ++i) {
					tmp1 = coeffs[xs][i];
					coeffs[xs][i] = coeffs[y][i];
					coeffs[y][i] = tmp1;
				}
					
			}
			
			for (y=xs+1; y<RC; ++y) if (coeffs[y][x])
			{
				for (z=xs; z<RC; z++) XOREGY(coeffs[y][z], coeffs[xs][z]);
				XOREGY(rights[y], rights[xs]);
			}
		 	xs++;
		 }
	}
	
	for (z = xs; z < RC; ++z) {
		if (rights[z]) {return false;}
	}
	
	
	for (int i=0; i<RC; ++i) variables[i] = 0;

	for (--xs; xs>=0; --xs)
	{
		for (x=0; !coeffs[xs][x]; ++x);
		variables[x] = rights[xs];
		for (z = x+1; z < RC; ++z) 
		{
			bool tmp = coeffs[x][z] && variables[z];
			XOREGY(variables[x], tmp);
		}
	}
	
	return true;
}

int main()
{ 
	for (int i=0; i<256; ++i) coeffs[i]= new bool[256];
	
	for (int i=0; i<256; ++i) for (int j=0; j<256; ++j) def_coeffs[i][j]=false;
	for (int x=0; x<16; ++x)
		for (int y=0; y<16; ++y)
		{
			int o = BC(x, y);
			def_coeffs[o][o] = true;
			if (x>0)
			{
				int a = BC(x-1, y);
				def_coeffs[o][a] = true;
				def_coeffs[a][o] = true;
			}
			if (y>0)
			{
				int a = BC(x, y-1);
				def_coeffs[o][a] = true;
				def_coeffs[a][o] = true;
			}		
		}
	
	
	while (scanf("%d %d ", &R, &C) && R)
	{
		RC = R*C;
		
		for (int x1=0; x1<R; ++x1 )
			for (int y1=0; y1<C; ++y1 )
			{
				for (int x2=0; x2<R; ++x2 )
					for (int y2=0; y2<C; ++y2 )
					{
					
						coeffs[COORD(x1, y1)][COORD(x2, y2)] = def_coeffs[BC(x1, y1)][BC(x2, y2)];
						
						//printf(">> %d,%d - %d,%d = %d\n", x1, y1, x2, y2, coeffs[COORD(x1, y1)][COORD(x2, y2)]);
					}				
			}
		
		char buf[70];
		for (int x=0; x<R; x++)
		{
			fgets(buf, 69, stdin);
			//%printf(">> %s", buf);
			
			for (int y=0; y<C; y++)
			{
				rights[COORD(x,y)] = buf[y] == 'X';
			}
			
		}
		
		if (solve())
		{
			int s = 0;
			for (int i=0; i<RC; ++i) 
			{
			//	printf(">> %d \n", variables[i]);
				s+=variables[i] ? 1 : 0;
			}
			printf("You have to tap %d tiles.\n", s);
		}
		else printf("Damaged billboard.\n");
	
	}
	
	return 0;
}