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#include <iostream>
#include <bits/stdc++.h>
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")

#define mp make_pair
#define pb push_back
#define eb emplace_back
#define x first
#define y second
#define sz(x) (int)x.size()
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
#define FOR(i,a,b) for (int i = (a); i < (b); i++)
#define RFOR(i,b,a) for (int i = (b) - 1; i >= (a); i--)

using namespace std;

typedef unsigned long long ull;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pi;
typedef pair<ld, ld> pld;
typedef pair<ll, ll> pl;
typedef vector<int> veci;
typedef vector<bool> vecb;
typedef vector<vector<int>> vvi;
typedef vector<vector<bool>> vvb;

const int INF_I = 1e9;
const ll INF_LL = 1e18;
const int MOD = 1000000007;
const double eps = 1e-6;

vector<vector<char>> g;

int main() {

    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);

    int n;
    cin >> n;
    g.assign(n, vector<char>());
    for (int i = 0; i < n-1; i++){
        g[i].assign(n-i-1, false);
        for (int j = 0; j < n-i-1; j++){
            char ch;
            cin >> ch;
            g[i][j] = (ch == 'R' ? 1 : 2);
        }
    }

    for (int i = 0; i < n - 1; i++){
        vector<char> t(n);
        t[i] = 3;
        for (int j = i; j < n - 1; j++)
            for (int k = j + 1; k < n; k++)
                t[k] |= (t[j] & g[j][k-j-1]);
        for (int j = i + 1; j < n; j++)
            if (t[j] == 3){
                cout << "NO\n";
                return 0;
            }
    }
    cout << "YES\n";

    return 0;
}