#include <bits/stdc++.h>
using namespace std;
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long int n;
  cin >> n;
  string s;
  cin >> s;
  long long int in = 0;
  for (long long int i = 1; i < n; i++) {
    if (s[i] == '?' || s[i - 1] == '?') continue;
    if (s[i - 1] == s[i]) in++;
  }
  if (in > 0) {
    cout << "No";
    return 0;
  }
  char ch1 = 'A', bh1;
  for (long long int i = 0; i < n; i++)
    if (s[i] != '?') {
      ch1 = s[i];
      break;
    }
  for (long long int i = n - 1; i >= 0; i--)
    if (s[i] != '?') {
      bh1 = s[i];
      break;
    }
  if (ch1 == 'A') {
    cout << "Yes";
    return 0;
  }
  s = ch1 + s;
  n += 2;
  s = s + bh1;
  char ch;
  long long int c = 0;
  long long int ans = 1;
  for (long long int i = 0; i < n; i++) {
    if (s[i] != '?') {
      if (c != 0) {
        if (ch != s[i] && c == 1)
          ans *= 1;
        else
          ans *= 2;
        c = 0;
      }
      ch = s[i];
    } else
      c++;
  }
  if (ans == 1)
    cout << "No";
  else
    cout << "Yes";
  return 0;
}
