#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <climits>
#include <cfloat>
#include <ctime>
#include <cassert>
#include <map>
#include <utility>
#include <set>
#include <iostream>
#include <memory>
#include <string>
#include <vector>
#include <algorithm>
#include <functional>
#include <sstream>
#include <complex>
#include <stack>
#include <queue>
#include <numeric>
#include <list>
#include <iomanip>
#include <fstream>
#include <bitset>
   
using namespace std;
   
 
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
#define foreach(it, c) for (__typeof__((c).begin()) it=(c).begin(); it != (c).end(); ++it)
#define rforeach(it, c) for (__typeof__((c).rbegin()) it=(c).rbegin(); it != (c).rend(); ++it)
#define all(c) (c).begin(), (c).end()
#define rall(c) (c).rbegin(), (c).rend()
#define CL(arr, val) memset(arr, val, sizeof(arr))
#define COPY(dest, src) memcpy(dest, src, sizeof(dest))
#define ten(n) ((long long)(1e##n))
#define bin(n) (1LL << (n))
#define erep(i, n) for (int i = 0; i <= (int)(n); ++i)
#define revrep(i, n) for (int i = (n); i >= 0; --i)
#define pb push_back

template <class T> void chmax(T& a, const T& b) { a = max(a, b); }
template <class T> void chmin(T& a, const T& b) { a = min(a, b); }

template <class T> void uniq(T& c) { sort(c.begin(), c.end()); c.erase(unique(c.begin(), c.end()), c.end()); }
 
template <class T> string to_s(const T& a) { ostringstream os; os << a; return os.str(); }
template <class T> T to_T(const string& s) { istringstream is(s); T res; is >> res; return res; }

template <typename T> void print_container(ostream& os, const T& c) { const char* _s = " "; if (!c.empty()) { __typeof__(c.begin()) last = --c.end(); foreach (it, c) { os << *it; if (it != last) cout << _s; } } }
template <typename T> ostream& operator<<(ostream& os, const vector<T>& c) { print_container(os, c); return os; }
template <typename T> ostream& operator<<(ostream& os, const set<T>& c) { print_container(os, c); return os; }
template <typename T> ostream& operator<<(ostream& os, const multiset<T>& c) { print_container(os, c); return os; }
template <typename T> ostream& operator<<(ostream& os, const deque<T>& c) { print_container(os, c); return os; }
template <typename T, typename U> ostream& operator<<(ostream& os, const map<T, U>& c) { print_container(os, c); return os; }
template <typename T, typename U> ostream& operator<<(ostream& os, const pair<T, U>& p) { os << "( " << p.first << ", " << p.second << " )"; return os; }

template <class T> void print(T a, int n, const string& deli = " ", int br = 1) { for (int i = 0; i < n; ++i) { cout << a[i]; if (i + 1 != n) cout << deli; } while (br--) cout << endl; }
template <class T> void print2d(T a, int w, int h, int width = -1, int br = 1) { for (int i = 0; i < h; ++i) { for (int j = 0; j < w; ++j) {    if (width != -1) cout.width(width); cout << a[i][j] << ' '; } cout << endl; } while (br--) cout << endl; }

template <class T> void input(T& a, int n) { for (int i = 0; i < n; ++i) cin >> a[i]; }
template <class T> void input(T* a, int n) { for (int i = 0; i < n; ++i) cin >> a[i]; }

void fix_pre(int n) { cout.setf(ios::fixed, ios::floatfield); cout.precision(10); }
void fast_io() { cin.tie(0); ios::sync_with_stdio(false); }
#define trace(x) (cout << #x << ": " << (x) << endl)
 
bool in_rect(int x, int y, int w, int h) { return 0 <= x && x < w && 0 <= y && y < h; }
bool in_seg(int n, int l, int r) { return l <= n && n < r; } // n in [l, r)?

typedef long long ll;
typedef pair<int, int> pint;
 
// y(v): v>^<  y(^): ^>v<
const int dx[] = { 0, 1, 0, -1 };
const int dy[] = { 1, 0, -1, 0 };

const double PI = acos(-1.0);
#define mp make_pair


int main()
{
    const int week_s = 7 * 24 * 60;
    const int S = 2 * 7 * 24 * 60;
    static int All[2][S], day[2][S], night[2][S];
    All[0][1] = 1, All[0][24 * 60 + 1] = -1;
    day[0][6 * 60 + 1] = 1, day[0][18 * 60 + 1] = -1;
    night[0][18 * 60 + 1] = 1, night[0][24 * 60 + 1] = -1;
    night[0][1] = 1, night[0][6 * 60 + 1] = -1;
    rep(i, 24 * 60 + 100)
    {
        All[0][i + 1] += All[0][i];
        day[0][i + 1] += day[0][i];
        night[0][i + 1] += night[0][i];
    }
    rep(i, 24 * 60)
    {
        rep(j, 7)
        {
            int ss = j * 24 * 60;
            All[1][i + ss] = All[0][i];
            day[1][i + ss] = day[0][i];
            night[1][i + ss] = night[0][i];
        }
    }

    int s, n, t;
    string weekday, time;
    int p, m;
    while (cin >> s >> n >> t >> weekday >> time >> p >> m, s)
    {
        int* trans = (time == "All" ? All : (time == "Day" ? day : night))[weekday == "All"];

        int max_chance = -1;
        rep(i, 7 * 24 * 60 + 10)
        {
            int chance = 0;
            rep(j, m)
            {
                int a = i + j * t;
                int b = a + s;
                if (trans[a % week_s] && trans[b % week_s])
                    ++chance;
            }
            chmax(max_chance, chance);
        }
        printf("%.12f\n", 1 - pow(1 - 1.0 / p, max_chance * n));
    }
}