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#include <iostream>
#include <vector>
#include <cassert>
#include <map>
#include <algorithm>
#include <limits.h>
using namespace std;

#define REP(a,n) for(int a=0;a<n;++a)
#define REP1(a,n) for(int a=1;a<=n;++a)
#define P(a) cout<<#a<<": "<<(a)<<endl
#define LL long long

#define assert(a) 1;
#define P(a) 1;
const int MAXN=1000*1000;

int n,m;

int mon[MAXN];
char d[MAXN+1];
bool visited[MAXN];
//bool added[MAXN];


//map<int,int> cycle;
vector<int> pref;
vector<int> prefMaxL;
vector<int> prefMaxR;

map<int,vector<int> > wys;

/*
 * |lllllllrrrrrrrrrr| <- pref sum array
 *         ^
 *         j   
 */

int ceil(int a,int b){
    return (a+b-1)/b;
}
LL check(int k,int j){
    P(k);
    P(j);
    // j is index in cycle
    int l=0;
    if(j>0)l=pref[j-1];
    int r=*pref.rbegin() - l;

    P(l);
    P(r);

    //int curMoney=0;

    // maximum in cycle
    int maxv=prefMaxR[j]-l;
    if(j>0)maxv=max(maxv,prefMaxL[j-1]+r);
    P(maxv);

    LL ret=0;

    if(maxv<k){
        if(*pref.rbegin()<=0)return -1;
        int cyclesCount=ceil(k-maxv,*pref.rbegin());
        P(cyclesCount);
        ret+=((LL)cyclesCount)*pref.size();
        k-=cyclesCount*(*pref.rbegin());
    }
    P(ret);
    P(k);

    if(k==0)return ret;

    P(k+l);
    vector<int>& vec=wys[k+l];
    for(auto a:vec){
        //cout<<a<<" ";
    }
    //cout<<endl;
    vector<int>::iterator iter=lower_bound(vec.begin(),vec.end(),j);
    P(iter==vec.end());
    if(iter==vec.end()){
        vector<int>& vec2=wys[k-r];
        assert(!vec2.empty());
        assert(vec2[0]<j);
        ret+=vec2[0]+1+r;
    }else{
        ret+=(*iter)-j+1;
    }

    return ret;
}


int main()
{
    //ios_base::sync_with_stdio(0);
    cin>>n;
    REP(a,n){
        cin>>mon[a];
    }
    cin>>m;
    cin>>d;

    int len=__gcd(n,m);
    int siz=m/len;
    LL ret=LLONG_MAX;
    P(len);
    P(siz);
    REP(a,len){
        pref.clear();
        prefMaxL.clear();
        prefMaxR.clear();
        //cycle.clear();
        wys.clear();
        int i=a;
        while(!visited[i]){
            //cycle[i]=pref.size();
            pref.push_back((d[i]=='W')?-1:1);
            visited[i]=1;
            i=(i+n)%m;
        }

        // making prefix sums
        //cout<<pref[0]<<" ";
        for(i=1;i<pref.size();++i){
            pref[i]+=pref[i-1];
            //cout<<pref[i]<<" ";
        }
        //cout<<endl;

        // making wys
        REP(a,pref.size()){
            wys[pref[a]].push_back(a);
        }

        // making prefix max from left
        prefMaxL.push_back(pref[0]);
        for(i=1;i<pref.size();++i){
            prefMaxL.push_back(max(pref[i-1],pref[i]));
        }

        // from right
        prefMaxR.push_back(pref[pref.size()-1]);
        for(i=pref.size()-2;i>=0;--i){
            prefMaxR.push_back(max(pref[i+1],pref[i]));
        }

        assert(siz==pref.size());
        assert(siz==prefMaxL.size());
        assert(siz==prefMaxR.size());

        for(i=a;i<n;i+=len){
            LL checkRet=check(mon[i],(i/len)&m);
            P(checkRet);
            ret=min(ret,(LL)i+(LL)(checkRet-1)*n +1);
            if(ret==-1){
                cout<<-1;
                return 0;
            }
        }
    }
    cout<<ret;
    return 0;
}