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#include<cstdio>
#define N 1000010
typedef long long ll;
const ll inf=2000000000000000000LL;
int n,m,i,j,k,x,a[N],b[N],v[N],t,q[N],s[N],pre[N],suf[N],g[N],c[N+N];ll f[N],ans=inf;char ch[N];
inline void read(int&a){char c;while(!(((c=getchar())>='0')&&(c<='9')));a=c-'0';while(((c=getchar())>='0')&&(c<='9'))(a*=10)+=c-'0';}
inline int min(int a,int b){return a<b?a:b;}
inline ll min(ll a,ll b){return a<b?a:b;}
int main(){
  for(read(n);i<n;i++)read(a[i]),f[i]=inf,g[i]=N;
  for(read(m),scanf("%s",ch),i=0;i<m;i++)b[i]=ch[i]=='W'?1:-1;
  for(i=0;i<N+N;i++)c[i]=N;
  for(i=0;i<n;i++)if(!v[i%m]){
    for(t=0,j=i%m;!v[j];j=(j+n)%m)v[q[++t]=j]=1;
    for(j=1;j<=t;j++)s[j]=s[j-1]+b[q[j]];
    pre[0]=suf[t+1]=N;
    for(j=1;j<=t;j++)pre[j]=min(pre[j-1],s[j]);
    for(j=t;j;j--)suf[j]=min(suf[j+1],s[j]);
    for(j=1;j<=t;j++){
      x=min(pre[j-1]+s[t],suf[j])-s[j-1];
      for(k=q[j];k<n;k+=m)if(x+a[k]<=0)g[k]=0;else if(s[t]<0)g[k]=(x+a[k])/(-s[t])+((x+a[k])%(-s[t])>0);
    }
    for(j=1;j<=t;j++){
      for(k=q[j];k<n;k+=m)if(g[k]<N){
        x=c[s[j-1]-g[k]*s[t]-a[k]-s[t]+N];
        if(x<=t)f[k]=min(f[k],(1LL*g[k]*t+x-j+t)*n+k);
      }
      if(c[s[j]+N]>j)c[s[j]+N]=j;
    }
    for(j=1;j<=t;j++)c[s[j]+N]=N;
    for(j=t;j;j--){
      c[s[j]+N]=j;
      for(k=q[j];k<n;k+=m)if(g[k]<N){
        x=c[s[j-1]-g[k]*s[t]-a[k]+N];
        if(x<=t)f[k]=min(f[k],(1LL*g[k]*t+x-j)*n+k);
      }
    }
    for(j=1;j<=t;j++)c[s[j]+N]=N;
  }
  for(i=0;i<n;i++)ans=min(ans,f[i]+1);
  if(ans<inf)printf("%lld",ans);else puts("-1");
  return 0;
}