#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <cstring>

#include <iostream>
#include <complex>
#include <string>
#include <algorithm>
#include <numeric>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <unordered_map>
#include <unordered_set>

#include <functional>
#include <cassert>

typedef long long ll;
using namespace std;

#ifndef LOCAL
#define debug(x) ;
#else
#define debug(x) cerr << __LINE__ << " : " << #x << " = " << (x) << endl;

template <typename T1, typename T2>
ostream &operator<<(ostream &out, const pair<T1, T2> &p) {
  out << "{" << p.first << ", " << p.second << "}";
  return out;
}

template <typename T>
ostream &operator<<(ostream &out, const vector<T> &v) {
  out << '{';
  for (const T &item : v) out << item << ", ";
  out << "\b\b}";
  return out;
}
#endif

#define mod 1000000007 //1e9+7(prime number)
#define INF 1000000000 //1e9
#define LLINF 2000000000000000000LL //2e18
#define SIZE 200010

ll dp[201][201][201]; //現在の順位, 上の空き, 下の数

int main(){
  int N;
  char c[200];

  scanf("%d", &N);

  for (int i=0; i<N; i++) {
    scanf(" %c", c+i);
  }

  dp[0][0][0] = 1;

  for (int i=0; i<N; i++) {
    for (int j=0; j<=i; j++) {
      for (int k=0; k<=i; k++) {
        if (c[i] == '-') {
          dp[i+1][j][k] = (dp[i+1][j][k] + dp[i][j][k]) % mod;
        }
        if (c[i] == 'D') {
          if (j > 0)
            dp[i+1][j][k] = (dp[i+1][j][k] + dp[i][j][k] * j) % mod;
          if (j > 0 && k > 0)
            dp[i+1][j-1][k-1] = (dp[i+1][j-1][k-1] + dp[i][j][k] * j * k) % mod;
        }
        if (c[i] == 'U') {
          dp[i+1][j+1][k+1] = (dp[i+1][j+1][k+1] + dp[i][j][k]) % mod;
          if (k > 0)
            dp[i+1][j][k] = (dp[i+1][j][k] + dp[i][j][k] * k) % mod;
        }
      }
    }
  }

  printf("%lld\n", dp[N][0][0]);

  return 0;
}

