#include<bits/stdc++.h>
using namespace std;
#define ll              long long
#define rep(i,a,b)        for(int i=a;i<b;i++)



void solve(){
    string s;
    cin >> s;
    int countl = 0 ,countu = 0;
    rep(i,0,s.size()){
          if((i+1) % 2 == 0){
               if(isupper(s[i]))countu++;
          }
          else{
                if(islower(s[i]))countl++;
          }
    } 
    if(countl + countu == s.size()){
          cout << "Yes\n";
    }
    else{
          cout << "No\n";
    }

}


int main(){
         ios_base::sync_with_stdio(false);
         cin.tie(0);cout.tie(0);
         solve();




}
#include<bits/stdc++.h>
#define ll long long
#define ff first
#define ss second
#define pb push_back
using namespace std;

const int N = 4e5+5, mod = 3;

int n;
ll A[N],f[N],g[N];
ll answer = 0;

int C(int a,int b){
    if(f[b] > f[a] + f[b-a]){
        return 0;
    }

    int x = 4*g[b]/g[a]/g[b-a];
    if(x == 1) return 4;
    if(x == 2) return 2;
    if(x == 4) return 1;
    if(x == 8) return 2;
}

inline void test_case(){

    cin >> n;
    for(int i = 1; i <= n; i++){
        char c;
        cin >> c;
        if(c == 'B') A[i] = 0;
        if(c == 'W') A[i] = 1;
        if(c == 'R') A[i] = 2;
    }

    f[0] = 0; g[0] = 1;
    for(int i = 1; i <= n; i++){
        int cnt = 0;
        ll y = g[i-1]*i;
        while(y%3 == 0){
            y /= 3;
            cnt++;
        }
        y %= 3;
        f[i] = f[i-1] + cnt;
        g[i] = y;
        //cout << f[i] << " " << g[i] << endl;
    }

    for(int i = 1; i <= n; i++){
        //cout << C(i-1,n-1) << endl;
        //cout << A[i] << endl;
        answer += A[i]*C(i-1,n-1);
        answer %= 3;
    }

    //cout << answer << endl;

    if(n%2 == 0) answer = (mod - answer)%mod;

    if(answer == 0) cout << 'B' << endl;
    if(answer == 1) cout << 'W' << endl;
    if(answer == 2) cout << 'R' << endl;
}

 main(){
    ios::sync_with_stdio(0);

    int T = 1;
    //cin >> T;
    while(T--){
        test_case();
    }
}
