#include <bits/stdc++.h>
using namespace std;
const int MOD = 1e9 + 7;
long long power(long long a, long long b) {
  long long ret = 1;
  while (b) {
    if (b & 1) ret *= a;
    a *= a;
    if (ret >= MOD) ret %= MOD;
    if (a >= MOD) a %= MOD;
    b >>= 1;
  }
  return ret;
}
long long inv(long long x) { return power(x, MOD - 2); }
const int N = 1e5 + 5;
int n, sum[N];
char A[N];
int main() {
  std::ios::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  cin >> n;
  int mx = 0;
  for (int i = 1; i <= n; i++) {
    cin >> A[i];
    if (A[i] != '?') {
      sum[i] = 0;
      continue;
    }
    sum[i] = sum[i - 1] + 1;
    mx = max(mx, sum[i]);
  }
  bool chk = 1;
  for (int i = 1; i + 1 <= n; i++)
    if (A[i] == A[i + 1] and A[i] != '?') chk = 0;
  if (!chk) {
    cout << "No";
    return 0;
  }
  if (mx >= 2) {
    cout << "Yes";
    return 0;
  }
  for (int i = 1; i <= n; i++) {
    if (A[i] == '?') {
      bool c = 1, m = 1, y = 1;
      if (i - 1 >= 1) {
        if (A[i - 1] == 'C')
          c = 0;
        else if (A[i - 1] == 'M')
          m = 0;
        else if (A[i - 1] == 'Y')
          y = 0;
      }
      if (i + 1 <= n) {
        if (A[i + 1] == 'C')
          c = 0;
        else if (A[i + 1] == 'M')
          m = 0;
        else if (A[i + 1] == 'Y')
          y = 0;
      }
      int val = c + m + y;
      if (val >= 2) {
        cout << "Yes";
        return 0;
      }
    }
  }
  cout << "No";
}
