#include <bits/stdc++.h>
using namespace std;
const double PI = acos(-1);
const double eps = 1e-9;
const int inf = 2000000000;
const long long infLL = 9000000000000000000;
inline bool checkBit(long long n, int i) { return n & (1LL << i); }
inline long long setBit(long long n, int i) {
  return n | (1LL << i);
  ;
}
inline long long resetBit(long long n, int i) { return n & (~(1LL << i)); }
inline bool EQ(double a, double b) { return fabs(a - b) < 1e-9; }
inline bool isLeapYear(long long year) {
  return (year % 400 == 0) || (year % 4 == 0 && year % 100 != 0);
}
inline void normal(long long &a) {
  a %= 1000000007;
  (a < 0) && (a += 1000000007);
}
inline long long modMul(long long a, long long b) {
  a %= 1000000007, b %= 1000000007;
  normal(a), normal(b);
  return (a * b) % 1000000007;
}
inline long long modAdd(long long a, long long b) {
  a %= 1000000007, b %= 1000000007;
  normal(a), normal(b);
  return (a + b) % 1000000007;
}
inline long long modSub(long long a, long long b) {
  a %= 1000000007, b %= 1000000007;
  normal(a), normal(b);
  a -= b;
  normal(a);
  return a;
}
inline long long modPow(long long b, long long p) {
  long long r = 1;
  while (p) {
    if (p & 1) r = modMul(r, b);
    b = modMul(b, b);
    p >>= 1;
  }
  return r;
}
inline long long modInverse(long long a) { return modPow(a, 1000000007 - 2); }
inline long long modDiv(long long a, long long b) {
  return modMul(a, modInverse(b));
}
int dx[] = {0, 0, +1, -1};
int dy[] = {+1, -1, 0, 0};
long long n, a[363310], ans = 1;
string s;
bool flag[363310];
set<long long> st;
set<long long>::iterator it;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> s >> a[i];
    if (s == "ADD") flag[i] = 1;
  }
  long long lef = -1, ri = 408983067, hand = 0;
  st.insert(lef);
  st.insert(ri);
  for (int i = 1; i <= n; i++) {
    if (flag[i]) {
      if (lef <= a[i] && a[i] <= ri) hand++;
      st.insert(a[i]);
    } else {
      if (lef != a[i] && ri != a[i]) ans = (ans * 2LL) % 1000000007;
      if (lef > a[i] || ri < a[i]) {
        cout << "0" << '\n';
        return 0;
      }
      st.erase(a[i]);
      it = st.lower_bound(a[i]);
      ri = *it;
      it--;
      lef = *it;
      hand = 0;
    }
  }
  ans = (ans * (hand + 1)) % 1000000007;
  cout << ans << '\n';
  return 0;
}
