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#define NDEBUG
#include <cassert>
#include <cctype>
#include <iostream>
#include <limits>
#include <unistd.h>
#include <vector>
using namespace std;

typedef long long LL;
typedef signed char int8;

class Input {
 public:
  Input() { bufpos = bufend = buffer; eof = false; }
  bool Eof() { return eof; }
  char Peek() { if(bufpos == bufend) Grab(); return *bufpos; }
  unsigned char UPeek() { return static_cast<unsigned char>(Peek()); }
  void SkipWS();
  template<class T> T Get();
  void operator()() {}
  template<class Arg, class... Args> void operator()(Arg &arg, Args &... args) {
    arg = Get<Arg>();
    operator()(args...);
  }
 private:
  static const int BUFSIZE = 1<<16;
  char buffer[BUFSIZE];
  char *bufpos;
  char *bufend;
  bool eof;
  void Grab();
};

void Input::Grab() {
  if(eof) return;
  bufpos = buffer;
  bufend = buffer + read(0, buffer, BUFSIZE);
  if(bufend==bufpos) { eof=true; *bufpos=0; }
}

template<> inline char Input::Get<char>() {
  char res = Peek();
  ++bufpos;
  return res;
}

void Input::SkipWS() {
  while(isspace(UPeek())) Get<char>();
}

template<> unsigned Input::Get<unsigned>() {
  SkipWS();
  unsigned x = 0;
  while(isdigit(UPeek())) {
    x = 10u * x + (Get<char>()-'0');
  }
  return x;
}

template<> int Input::Get<int>() {
  SkipWS();
  bool neg = false;
  if(Peek()=='-') { neg=true; Get<char>(); }
  unsigned x = Get<unsigned>();
  if (neg) x = -x;
  return static_cast<int>(x);
}

Input IN;

// ------------------

int numPlayers, winCycleLen;
vector<int> initialMoney;
vector<int8> winCycle;

void ReadInput() {
  IN(numPlayers);
  initialMoney.resize(numPlayers);
  for (int &m : initialMoney) IN(m);
  IN(winCycleLen);
  winCycle.resize(winCycleLen);
  IN.SkipWS();
  for (int8 &win : winCycle) {
    char c; IN(c);
    assert(c=='W' || c=='P');
    win = (c=='W') ? +1 : -1;
  }
}

int Gcd(int a, int b) {
  return b==0 ? a : Gcd(b, a%b);
}

long long SolveCycle(const int start, const int subcycleLen, const int stepBack,
                     vector<int> &firstSeen) {
  firstSeen.assign(4 * subcycleLen + 1, -1);
  const int endCash = 2 * subcycleLen;
  int t = 2 * subcycleLen;
  int idx = start;
  int cash = endCash;
  int minSeen = cash;
  firstSeen[cash] = t;
  int lostPerCycle = 0;
  long long res = numeric_limits<long long>::max();
  while (t > 0) {
    --t;
    idx = (idx + stepBack) % winCycleLen;
    cash -= winCycle[idx];
    if (cash < minSeen) minSeen = cash;
    firstSeen[cash] = t;
    if (t == subcycleLen) {
      assert(idx == start);
      lostPerCycle = cash - endCash;
    } else if (t < subcycleLen) {
      for (int player = idx; player < numPlayers; player += winCycleLen) {
        int want = cash - initialMoney[player];
        long long tZero;
        if (want >= minSeen) {
          tZero = firstSeen[want] - t;
        } else if (lostPerCycle > 0) {
          const int fullCycles =
            (minSeen - want + lostPerCycle - 1) / lostPerCycle;
          int wantLater = want + fullCycles * lostPerCycle;
          assert(wantLater >= minSeen && wantLater <= cash);
          tZero = firstSeen[wantLater] - t + LL(subcycleLen) * fullCycles;
        } else {
          continue;
        }
        res = min(res, player + 1 + (tZero-1) * numPlayers);
      }
    }
  }
  return res;
}

long long Solve() {
  long long res = numeric_limits<long long>::max();
  int g = Gcd(numPlayers, winCycleLen);
  vector<int> helper;
  int stepBack = (winCycleLen - numPlayers % winCycleLen) % winCycleLen;
  for (int start = 0; start < g; ++start) {
    res = min(res, SolveCycle(start, winCycleLen / g, stepBack, helper));
  }
  return res;
}

int main() {
  ReadInput();
  long long res = Solve();
  if (res == numeric_limits<long long>::max()) {
    res = -1;
  }
  cout << res << '\n';
}