int main()
{
    int n,sum=0,m;
	cin>>n;
	char a[100][100],b[100][100];
	int i,j,k;
	for(i=0;i<n;i++)
	{
		for(j=0;j<n;j++)
		{
			cin>>a[i][j];
			b[i][j]=a[i][j];
		}
	}
	cin>>m;
	while(m>1)
	{
	for(i=0;i<n;i++)
	{
		for(j=0;j<n;j++)
		{   
			if(a[i][j]=='@')	
			{if(i>0&&j>0&&i<n-1&&j<n-1)
				{
				if(a[i-1][j]=='.')
					b[i-1][j]='@';
                 if(a[i+1][j]=='.')
					b[i+1][j]='@';
			     if(a[i][j-1]=='.')
					b[i][j-1]='@';
			     if(a[i][j+1]=='.')
					 b[i][j+1]='@';}
				
				if(i==0&&j<n-1&&j>0)
				{ 
					
					if(a[i][j+1]=='.')
						b[i][j+1]='@';
					if(a[i+1][j]=='.')
						b[i+1][j]='@';
					if(a[i][j-1]=='.')
						b[i][j-1]='@';
					
				}
				if(i==0&&j==0)
				{
					
					
						if(a[i+1][j]=='.')
							b[i+1][j]='@';
						if(a[i][j+1]=='.')
							b[i][j+1]='@';
					
				}
				if(i==n-1&&j<n-1&&j>0)
				{  
					
					if(a[i][j+1]=='.')
						b[i][j+1]='@';
					if(a[i-1][j]=='.')
						b[i-1][j]='@';
					if(a[i][j-1]=='.')
					   b[i][j-1]='@';
				}
				if(i==n-1&&j==0)
				{
                 
				   
					   if(a[i][j+1]=='.')
						   b[i][j+1]='@';
					   if(a[i-1][j]=='.')
						   b[i-1][j]='@';
				   
				}
				if(j==0&&i<n-1&&i>0)
				{
					
					if(a[i+1][j]=='.')
						b[i+1][j]='@';
					if(a[i][j+1]=='.')
						b[i][j+1]='@';
					if(a[i-1][j]=='.')
					b[i-1][j]='@';
				}
				if(j==n-1&&i<n-1&&i>0)
				{
					
					if(a[i+1][j]=='.')
						b[i+1][j]='@';
					if(a[i][j-1]=='.')
						b[i][j-1]='@';
					if(a[i-1][j]=='.')
					b[i-1][j]='@';
				}
				if(j==n-1&&i==0)
				{
					
					
						if(a[i][j-1]=='.')
							b[i][j-1]='@';
						if(a[i+1][j]=='.')
							b[i+1][j]='@';
					
				}
				if(j==n-1&&i==n-1)
				{
					
					if(a[i-1][j]=='.')
                       b[i-1][j]='@';
					if(a[i][j-1]=='.')
						b[i][j-1]='@';
				}
			}
		}
	}for(i=0;i<n;i++)
	{
		for(j=0;j<n;j++)
		a[i][j]=b[i][j];
	}
	m--;
	}
	for(i=0;i<n;i++)
	{
		for(j=0;j<n;j++)
		{
			if(a[i][j]=='@')
				sum++;
		}
	}
	cout<<sum;
	return 0;
}