b.cpp

#include<iostream>
#include<cmath>
#include<cstdio>

using namespace std;

#define rep(i, n) for (int i = 0; i < int(n); ++i)

int main() {
  while (true) {
    int s, n, t, p, m;
    string day, time;
    cin >> s >> n >> t >> day >> time >> p >> m;
    if (s == 0) break;
    bool allday, alltime;
    allday = (day == "All");
    alltime = (time == "All");
    int T;
    long long cnt = 0;
    rep (_T, 1440 * 7) {
      T = _T;
      long long c = 0;
      rep (mm, m) {
	bool flag = true;
	rep (tt, t) {
	  ++T;
	  if (tt < s) {
	    if (allday && alltime) {
	    } else if (allday && !alltime) {
	      if (T % (24 * 60) >= (12 * 60)) flag = false;
	    } else if (!allday && alltime) {
	      if (T % (24 * 60 * 7) >= (24 * 60)) flag = false;
	    } else {
	      if (time == "Day") {
		if (T % (24 * 60 * 7) >= (12 * 60)) flag = false;
	      } else {
		int t2 = T % (24 * 60 * 7);
		if (!((t2 < 6 * 60) || (18 * 60 < t2 &&t2 < 24 * 60))) flag = false;
	      }
	    }
	  }
	}
	if (flag) c += n;
      }
      cnt = max(cnt, c);
    }
    double res = 1 - pow(1.0 - 1.0 / p, cnt);
    printf("%.12lf\n", res);
  }
  return 0;
}