#include <bits/stdc++.h>
template <typename T>
void MACRO_VAR_Scan(T& t) {
  std::cin >> t;
}
template <typename First, typename... Rest>
void MACRO_VAR_Scan(First& first, Rest&... rest) {
  std::cin >> first;
  MACRO_VAR_Scan(rest...);
}
template <typename T>
void MACRO_VEC_ROW_Init(int n, T& t) {
  t.resize(n);
}
template <typename First, typename... Rest>
void MACRO_VEC_ROW_Init(int n, First& first, Rest&... rest) {
  first.resize(n);
  MACRO_VEC_ROW_Init(n, rest...);
}
template <typename T>
void MACRO_VEC_ROW_Scan(int p, T& t) {
  std::cin >> t[p];
}
template <typename First, typename... Rest>
void MACRO_VEC_ROW_Scan(int p, First& first, Rest&... rest) {
  std::cin >> first[p];
  MACRO_VEC_ROW_Scan(p, rest...);
}
template <class T>
inline T CHMAX(T& a, const T b) {
  return a = (a < b) ? b : a;
}
template <class T>
inline T CHMIN(T& a, const T b) {
  return a = (a > b) ? b : a;
}
template <class T>
std::vector<std::vector<T>> VV(int n, int m, T init = T()) {
  return std::vector<std::vector<T>>(n, std::vector<T>(m, init));
}
template <typename S, typename T>
std::ostream& operator<<(std::ostream& os, std::pair<S, T> p) {
  os << "(" << p.first << ", " << p.second << ")";
  return os;
}
using ll = long long;
using ull = unsigned long long;
using ld = long double;
using PAIR = std::pair<ll, ll>;
using PAIRLL = std::pair<ll, ll>;
constexpr ll INFINT = 1 << 30;
constexpr ll INFINT_LIM = (1LL << 31) - 1;
constexpr ll INFLL = 1LL << 60;
constexpr ll INFLL_LIM = (1LL << 62) - 1 + (1LL << 62);
constexpr double EPS = 1e-10;
constexpr ll MOD = 1000000007;
constexpr double PI = 3.141592653589793238462643383279;
template <class T, size_t N>
void FILL(T (&a)[N], const T& val) {
  for (auto& x : a) x = val;
}
template <class ARY, size_t N, size_t M, class T>
void FILL(ARY (&a)[N][M], const T& val) {
  for (auto& b : a) FILL(b, val);
}
template <class T>
void FILL(std::vector<T>& a, const T& val) {
  for (auto& x : a) x = val;
}
template <class ARY, class T>
void FILL(std::vector<std::vector<ARY>>& a, const T& val) {
  for (auto& b : a) FILL(b, val);
}
signed main() {
  std::ios::sync_with_stdio(false);
  std::cin.tie(0);
  ;
  ll n;
  MACRO_VAR_Scan(n);
  ;
  std::set<ll> sell, buy, unknown;
  ll ans = 1;
  for (ll _ = 0; _ < ll(n); ++_) {
    std::string type;
    MACRO_VAR_Scan(type);
    ;
    ll p;
    MACRO_VAR_Scan(p);
    ;
    if (type.back() == 'D') {
      if (!sell.empty() && *sell.begin() < p)
        sell.insert(p);
      else if (!buy.empty() && p < *buy.rbegin())
        buy.insert(p);
      else
        unknown.insert(p);
    } else {
      if (sell.count(p)) {
        if (p != *sell.begin()) {
          ans = 0;
          break;
        }
        sell.erase(p);
      } else if (buy.count(p)) {
        if (p != *buy.rbegin()) {
          ans = 0;
          break;
        }
        buy.erase(p);
      } else if (unknown.count(p)) {
        (ans *= 2) %= MOD;
        unknown.erase(p);
      }
      for (auto& x : unknown) {
        if (x < p)
          buy.insert(x);
        else if (p < x)
          sell.insert(x);
      }
      unknown.clear();
    }
  }
  (ans *= (ll)unknown.size() + 1) %= MOD;
  std::cout << (ans);
  std::cout << "\n";
  ;
  return 0;
}
