C

#include <algorithm>
#include <iostream>
#include <iomanip>
#include <vector>
#include <array>
#include <set>
#include <map>

using namespace std;

#define int long long

const long long INF = 1e18 + 7;
const int MAXN = 1e1 + 100;
const int N = 3e5 + 10;
const int MOD = 1e9 + 7;

int dp[1 << 19];
bool a[18][18];

signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);

    freopen("network.in", "r", stdin);
    freopen("network.out", "w", stdout);

    int n;
    cin >> n;
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < n; ++j) {
            char c;
            cin >> c;
            a[i][j] = (c == 'Y' ? 1 : 0);
        }
    }
    for (int mask = 0; mask < (1 << n); ++mask) {
        for (int x = 0; x < n; ++x) {
            if (mask & (1 << x)) continue;
            for (int y = 0; y < n; ++y) {
                if (mask & (1 << y)) continue;
                if (a[x][y]) {
                    int new_mask = mask | (1 << x) | (1 << y);
                    dp[new_mask] = max(dp[new_mask], dp[mask] + 2);
                }
            }
        }
    }
    int ans = 0;
    for (int mask = 0; mask < (1 << n); ++mask) {
        ans = max(ans, dp[mask]);
    }
    cout << ans << '\n';
}