#include <algorithm>
#include <cassert>
#include <iostream>
#include <string>
using namespace std;

const int MAX_N = 1100;
int n;
int a[MAX_N];
int used[MAX_N][MAX_N];
string s, t;
int max_depth = MAX_N * MAX_N;

bool dfs(const int l, const int r, const int val) {
    used[l][r] = val;
    if(l == r) {
        max_depth = val;
        return true;
    }
    if(max_depth == val) return false;
    bool res = false;
    for(auto &dl : {1, -1}) for(auto &dr : {-1, 1}) {
        int nl = l + dl,
            nr = r + dr;
        if(0 <= nl && nr <= n && a[nl] == a[nr] && (used[nl][nr] == 0 || used[nl][nr] > val + 1)) {
            res = res | dfs(nl, nr, val+1);
        }
    }
    return res;
}

int main() {
    cin >> n;
    for(int i = 0; i <= n; i++) cin >> a[i];
    if(dfs(0, n, 1)) {
        long long val = n*n;
        int l = 0, r = 0;
        for(int i = 0; i <= n; i++) {
            if(0 < used[i][i] && used[i][i] < val) {
                val = used[i][i];
                l = r = i;
            }
        }
        while(val > 1) {
            for(auto &dl : {1, -1}) for(auto &dr : {-1, 1}) {
                int nl = l + dl,
                    nr = r + dr;
                if(0 <= nl && nr <= n && used[nl][nr] + 1 == val) {
                    l = nl;
                    r = nr;
                    val = used[l][r];
                    s += dl == 1 ? 'L' : 'R';
                    t += dr == 1 ? 'L' : 'R';
                    break;
                }
            }
        }
        cout << "Yes" << endl;
        reverse(s.begin(), s.end());
        reverse(t.begin(), t.end());
        cout << s.size() << endl;
        cout << s << endl;
        cout << t << endl;
    } else {
        cout << "No" << endl;
    }
}