#include <cstdio>#include <cstring>#include <iostream>#include <algorithm>using namespace std;const int N = 25;const int Mod = 100000007;int Power(int x, int cf) { if (cf == 0) return 1; long long ret = Power(x, cf >> 1); ret = ret * ret % Mod; if (cf & 1) ret = ret * x % Mod; return ret;}long long C(int m, int n) { if (n < 0 || n > m || m < 0) return 0; long long up = 1; long long down = 1; for (int i = m - n + 1; i <= m; i++) up = up * i % Mod; for (int i = 1; i <= n; i++) down = down * i % Mod; return up * Power(down, Mod - 2) % Mod;}int n, m, s;char Str[100];char S1[100];char S2[100];int a[N];long long ans;void dfs(int p, int sum, int t) { if (sum < 1) return; if (p > m) { if (t & 1) ans -= C(sum - 1, n - 1); else ans += C(sum - 1, n - 1); ans = (ans % Mod + Mod) % Mod; return; } dfs(p + 1, sum, t); dfs(p + 1, sum - a[p], t + 1);}int main() { while (scanf("%d%d", &n, &s) != EOF) { if (n == 0) break; gets(Str); m = 0; s += n; bool check = true; while (1) { if (!gets(Str)) break; if (strlen(Str) < 2) break; int Num; sscanf(Str, "%s%s%s%d", S1, S1, S2, &Num); Num++; if (S1[0] == 'l') { a[++m] = Num - 1; if (Num == 1) check = false; } else s -= Num; } if (!check) printf("0n"); else { ans = 0; dfs(1, s, 0); printf("%dn", ans); } }}
