#include <stdio.h>
#include <string.h>

char matrix[35][35];
int m[35][35];
int N;
char ch;

void INIT(int x, int y)
{
    m[x][y] = 1;
    if (x + 1 <= N && matrix[x+1][y] != '#' && m[x+1][y] != 1)
INIT(x+1, y);
    if (x - 1 >= 1 && matrix[x-1][y] != '#' && m[x-1][y] != 1)
INIT(x-1, y);
    if (y + 1 <= N && matrix[x][y+1] != '#' && m[x][y+1] != 1)
INIT(x, y+1);
    if (y - 1 >= 1 && matrix[x][y-1] != '#' && m[x][y-1] != 1)
INIT(x, y-1);

    return;
}

int main()
{
    int i, j, total;

    scanf("%d", &N);
    ch = getchar();
    for (i = 1; i <= N; ++i) {
        for (j = 1; j <= N; ++j)
            matrix[i][j] = getchar();
        ch = getchar();
    }

    INIT(1, 1);
    INIT(N, N);

    total = 0;
    for (i = 1; i <= N; ++i ) {
        for (j = 1; j <= N; ++j) {
            if (m[i][j] == 1) {
                if (m[i+1][j] == 0 || i+1 > N)
total++;
                if (m[i-1][j] == 0 || i-1 < 1)
total++;
                if (m[i][j+1] == 0 || j+1 > N)
total++;
                if (m[i][j-1] == 0 || j-1 < 1)
total++;
            }
        }
    }

    total -= 4;
    printf("%d\n", total*9);
    return 0;
}