#include <bits/stdc++.h>
using namespace std;
long long int n;
set<long long int> nos;
long long powmod(long long x, long long y, long long m) {
  long long res = 1LL;
  while (y) {
    if (y & 1) res = (res * x) % m;
    x = (x * x) % m;
    y /= 2;
  }
  return res;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  cin >> n;
  long long int ans = 1;
  long long int buyt = 0;
  long long int selt = INT64_MAX;
  for (long long int i = 1; i <= n; i++) {
    string s;
    long long int val;
    cin >> s >> val;
    if (s == "ADD")
      nos.insert(val);
    else {
      nos.erase(val);
      if (buyt < val && selt > val)
        ans = (ans * 2) % 1000000007;
      else if (buyt == val || selt == val)
        ans = (ans * 1) % 1000000007;
      else
        ans = 0;
      auto it = nos.upper_bound(val);
      auto it1 = nos.lower_bound(val);
      if (it != nos.end())
        selt = *it;
      else
        selt = INT64_MAX;
      if (it1 != nos.begin()) {
        it1--;
        buyt = *it1;
      } else {
        buyt = 0;
      }
    }
  }
  long long int m = 0;
  for (auto it = nos.begin(); it != nos.end(); it++) {
    long long int temp = *it;
    if (temp > buyt && temp < selt) m++;
  }
  ans = (ans * (m + 1)) % 1000000007;
  cout << ans << "\n";
}
