D

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <vector>

using namespace std;

vector<vector<bool> > a;
vector<vector<bool> > use;
int dx[6] = {0, 0, 1, 1, -1, -1};
int dy[6] = {1, -1, 0, -1, 1, 0};
int n;

bool check(int x, int y) {
    return x >= 0 && y >= 0 && x < n && y < n;
}

bool dfs(int x, int y) {
    if (x == n - 1)
        return true;
    use[x][y] = true;
    for (int i = 0; i < 6; ++i) {
        int new_x = x + dx[i];
        int new_y = y + dy[i];
        if (check(new_x, new_y) && !use[new_x][new_y] && a[new_x][new_y])
            if (dfs(new_x, new_y))
                return true;
    }
    return false;
}

int main() {
    cin >> n;
    a.resize(n);
    for (int i = 0; i < n; ++i)
        for (int j = 0; j < n; ++j) {
            char p;
            cin >> p;
            if (p == 'W')
                a[i].push_back(true);
            else
                a[i].push_back(false);
        }
    use = vector<vector<bool> >(n, vector<bool>(n, false));
    for (int i = 0; i < n; ++i) {
        if (!use[0][i] && a[0][i]) {
            if (dfs(0, i)) {
                cout << "YES";
                return 0;
            }
        }
    }
    cout << "NO";
    return 0;
}