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#include <algorithm>
#include <cstdio>
#include <deque>
#include <limits>
#include <vector>
using namespace std;
typedef long long i64;

int gcd(int x, int y)
{
  while (y != 0)
  {
    int z = x%y;
    x = y;
    y = z;
  }
  return x;
}

struct S
{
  S(const vector<int>& t);
  inline int get(int i, int j);

  vector<int> sum_;
};

S::S(const vector<int>& t) : sum_(t.size()+1)
{
  for (int i=1; i<=(int)t.size(); ++i)
    sum_[i] = sum_[i-1] + t[i-1];
}

int S::get(int i, int j)
{
  if (j < (int)sum_.size()-1)
    return sum_[j+1] - sum_[i];
  else
    return sum_.back() - sum_[i] + sum_[j-((int)sum_.size()-1)+1];
}

struct Problem
{
  Problem(int n) : n_(n), m_(-1), g_(-1), a_(n) {}
  
  void setM(int m);
  i64 solve();
  i64 solveCycle(int r);
  vector<int> getCycleBs(int r);
  vector<int> getCycleIxs(int r);
  
  int n_,m_,g_;
  vector<int> a_,b_;
};

void Problem::setM(int m)
{
  m_ = m;
  g_ = gcd(n_,m);
  b_.resize(m);
}

i64 Problem::solve()
{
  i64 result = numeric_limits<i64>::max();
  for (int i=0; i<g_; ++i)
    result = min(result, solveCycle(i));
  return result == numeric_limits<i64>::max() ? -1 : result;
}

i64 Problem::solveCycle(int r)
{
  vector<int> ccb = getCycleBs(r);
  S ccbs(ccb);
  vector<int> ccix = getCycleIxs(r);
  deque<int> st;
  pair<int,int> first0(numeric_limits<int>::max(), 0);
  int minScore = numeric_limits<int>::max();
  for (int i=0; i<2*(m_/g_)-1; ++i)
  {
    if (i < m_/g_)
    {
      if (ccix[i] != -1)
      {
        while (!st.empty() && a_[ccix[st.back()]] + ccbs.get(st.back(),i-1) >= a_[ccix[i]]) st.pop_back();
        st.push_back(i);
      }
    }
    else if (!st.empty() && st[0] == i-m_/g_)
      st.pop_front();
    
    if (st.empty())
      continue;
    int score = a_[ccix[st[0]]] + ccbs.get(st[0],i);
    minScore = min(minScore, score);
    if (score == 0)
    {
      first0 = min(first0, make_pair(i-st[0], ccix[st[0]]));
      st.pop_front();
    }
  }
  if (minScore == 0)
    return (i64)first0.first*n_ + first0.second + 1;
  int bsum = ccbs.get(0,m_/g_-1);
  if (bsum >= 0)
    return numeric_limits<i64>::max();
  bsum = -bsum;
  int k = (minScore+bsum-1)/bsum;
  for (int ix : ccix)
    if (ix != -1)
      a_[ix] -= k*bsum;
  return k*((i64)n_*(m_/g_)) + solveCycle(r);
}

vector<int> Problem::getCycleBs(int r)
{
  vector<int> ccb(m_/g_);
  for (int& x : ccb)
  {
    x = b_[r];
    r = (r+n_)%m_;
  }
  return ccb;
}

vector<int> Problem::getCycleIxs(int r)
{
  vector<int> ccix(m_/g_, -1);
  for (int& x : ccix)
  {
    int q = r;
    while (q < n_)
    {
      if (x == -1 || (a_[q] < a_[x] || (a_[q]  == a_[x] && q < x)))
        x = q;
      q += m_;
    }
    r = (r+n_)%m_;
  }
  return ccix;
}

int main()
{
  int n;
  scanf("%d", &n);
  Problem p(n);
  for (int& x : p.a_)
    scanf("%d", &x);
  int m;
  scanf("%d", &m);
  p.setM(m);
  vector<char> tmp(m+1);
  scanf("%s", &tmp[0]);
  for (int i=0; i<m; ++i)
  {
    if (tmp[i] == 'W') p.b_[i] = 1;
    else p.b_[i] = -1;
  }
  printf("%lld\n", p.solve());
}