#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <climits>
#include <cfloat>
#include <ctime>
#include <cassert>
#include <map>
#include <utility>
#include <set>
#include <iostream>
#include <memory>
#include <string>
#include <vector>
#include <algorithm>
#include <functional>
#include <sstream>
#include <complex>
#include <stack>
#include <queue>
#include <numeric>
#include <list>
#include <iomanip>
   
using namespace std;
   
 
#ifdef __GNUC__
template <class T> int popcount(T n);
template <> int popcount(unsigned int n) { return __builtin_popcount(n); }
template <> int popcount(int n) { return __builtin_popcount(n); }
template <> int popcount(unsigned long long n) { return __builtin_popcountll(n); }
template <> int popcount(long long n) { return __builtin_popcountll(n); }
#else
#define __typeof__ decltype
template <class T> int popcount(T n) { return n ? 1 + popcount(n & (n - 1)) : 0; }
#endif
 
#define rep(i, n) for (int i = 0; i < (int)n; ++i)
#define foreach(it, c) for (__typeof__((c).begin()) it=(c).begin(); it != (c).end(); ++it)
#define rforeach(it, c) for (__typeof__((c).rbegin()) it=(c).rbegin(); it != (c).rend(); ++it)
#define all(c) (c).begin(), (c).end()
#define rall(c) (c).rbegin(), (c).rend()
#define CL(arr, val) memset(arr, val, sizeof(arr))
#define COPY(dest, src) memcpy(dest, src, sizeof(dest))
   
template <class T> void max_swap(T& a, const T& b) { a = max(a, b); }
template <class T> void min_swap(T& a, const T& b) { a = min(a, b); }

template <class T> void sort(vector<T>& c) { sort(c.begin(), c.end()); }
template <class T> void unique(vector<T>& c) { sort(c.begin(), c.end()); c.erase(unique(c.begin(), c.end()), c.end()); }
 
typedef long long ll;
typedef pair<int, int> pint;
   
template <class T, class U> ostream& operator<<(ostream& os, pair<T, U>& p) { os << "( " << p.first << ", " << p.second << " )"; return os;  }
  
template <class T> string to_s(const T& a) { ostringstream os; os << a; return os.str(); }
template <class T> T to_T(const string& s) { istringstream is(s); T res; is >> res; return res; }
  
bool valid(int x, int y, int w, int h) { return 0 <= x && x < w && 0 <= y && y < h; }
   
template <class T> void print(T a, int n, const string& deli = " ", int br = 1) { for (int i = 0; i < n; ++i) { cout << a[i]; if (i + 1 != n) cout << deli; } while (br--) cout << endl; }
template <class T> void print(const T& c, const string& deli = " ", int br = 1) { foreach (it, c) { cout << *it; if (++it != c.end()) cout << deli;--it; } while (br--) cout << endl; }
template <class T> void print2d(T a, int w, int h, int width = -1, int br = 1) { for (int i = 0; i < h; ++i) { for (int j = 0; j < w; ++j) {    if (width != -1) cout.width(width); cout << a[i][j] << ' '; } cout << endl; } while (br--) cout << endl; }
   
template <class T> void input(T& a, int n) { for (int i = 0; i < n; ++i) cin >> a[i]; }
template <class T> void input(T* a, int n) { for (int i = 0; i < n; ++i) cin >> a[i]; }

void fast_io() { cin.tie(0); ios::sync_with_stdio(false); }
#define trace(x) (cout << #x << ": " << (x) << endl)


const int dx[] = { 0, 1, 0, -1 };
const int dy[] = { 1, 0, -1, 0 };
  
const double PI = acos(-1.0);
const int mod = 1000000007;




int main()
{
    int n;
    char c[222];
    cin >> n;
    input(c, n);

    // dp[i + 1][j] (iまでみた, iまでで、空いている順位の数(== まだ決定してないチームの数))
    ll dp[222][222] = {};
    dp[0][0] = 1;
    for (int i = 0; i < n; ++i)
    {
        for (int j = 0; j <= i; ++j)
        {
            if (c[i] == 'U')
            {
                // ↑
                (dp[i + 1][j] += dp[i][j] * j) %= mod;
                // ↓
                (dp[i + 1][j + 1] += dp[i][j]) %= mod;
            }
            else if (c[i] == 'D')
            {
                // ↑
                if (j >= 1)
                    (dp[i + 1][j - 1] += dp[i][j] * j * j) %= mod;
                // ↓
                (dp[i + 1][j] += dp[i][j] * j) %= mod;
            }
            else
                dp[i + 1][j] = dp[i][j];
        }
    }
    cout << dp[n][0] << endl;
}

Measured memory_bytes: 1548