

int main()

{

    char a[110][110];

    char b[110][110];

    int n,m;

    int i,j,k;

    scanf("%d",&n);

    for(i=1;i<=n;i++)

        scanf("%s",a[i]+1);

    scanf("%d",&m);

    for(k=1;k<m;k++)

    {

        for(i=1;i<=n;i++)

        {

            for(j=1;j<=n;j++)

            {

                if(a[i][j] == '.' &&

                    (

                        a[i-1][j] == '@' ||

                        a[i][j-1] == '@' ||

                        a[i+1][j] == '@' ||

                        a[i][j+1] == '@'

                    ))

                    b[i][j] = '@';

                else

                    b[i][j] = a[i][j];

            }

        }

        for(i=1;i<=n;i++)

        {

            for(j=1;j<=n;j++)

            {

                a[i][j] = b[i][j];

                //printf("%c",a[i][j]);

            }

            //printf("\n");

        }

    }

    int sum = 0;

    for(i=1;i<=n;i++)

    {

        for(j=1;j<=n;j++)

        {

            if(a[i][j] == '@')

                sum++;

        }

    }

    printf("%d\n", sum);

    return 0;

}

