#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
//#pragma GCC optimize("O3") // optimization
//#pragma GCC optimize("Ofast") // optimization
//#pragma GCC optimize("unroll-loops") // optimization
#define ordered_set tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update>
#define ordered_multiset tree<int,null_type,less_equal<int>,rb_tree_tag,tree_order_statistics_node_update>
using namespace std;
#define i32 signed
#define int long long // CP
#define i64 long long
#define endl '\n'
#define elif else if
#define fi first
#define se second
#define pb push_back
#define p32 pair<i32,i32>
#define p64 pair<i64,i64>
#define f2(i,x) for((i)=0;(i)<(x);(i)++)
#define f2b(i,x) for((i)=(x)-1;(i)>=0;(i)--)
#define f3(i,f,t) for((i)=(f);(i)<(t);(i)++)
#define fall(x) (x).begin(), (x).end()
#define sort1(x) sort(fall(x))
#define rev(x) reverse(fall(x))
#define fast ios::sync_with_stdio(0);cin.tie(0);cout.tie(0)
#define fl fflush(stdout)
#define nl cout<<endl;fflush(stdout)
i64 gcd(i64 a, i64 b){if(a<b){a=a^b;b=a^b;a=a^b;} return b==0?a:gcd(b,a%b);}
i64 lcm(i64 a, i64 b){return a/gcd(a,b)*b;}
i64 expm(i64 a, i64 b, i64 m){i64 r=1;while(b){if(b&1)r=r*a%m;a=a*a%m;b>>=1;}return r%m;}
i64 expm(i64 a, i64 b){i64 r=1,m=1e9+7;while(b){if(b&1)r=r*a%m;a=a*a%m;b>>=1;}return r%m;}
i64 minv(i64 a, i64 m){return expm(a,m-2,m);}
i64 ncrm(i64 n, i64 r, i64 m){i64 i,j,k; i64 out=1; f3(i,1,n+1){out*=i;out%=m;}f3(i,1,r+1){out*=minv(i,m);out%=m;}f3(i,1,n-r+1){out*=minv(i,m);out%=m;}return out%m;}
// int n,m,k,a[300010],b[300010],c[300010];
double dist(p64 a,p64 b){
    return sqrt((double)(a.fi-b.fi)*(a.fi-b.fi)+(a.se-b.se)*(a.se-b.se));
}
void probA(){
    int i,j,l;
}void probB(){
    int i,j,l,n;
    cin>>n; string s; cin>>s;
    vector<p64>a,b;
    for(i=0;i<n;i++){
        int x,y; cin>>x>>y;
        if(s[i]=='G') a.pb({x,y});
        else b.pb({x,y});
    } int as=a.size(),bs=b.size();
    double ans=0;
    for(i=0;i<as/2;i++) ans+=dist(a[i],a[i+as/2]);
    for(i=0;i<bs/2;i++) ans+=dist(b[i],b[i+bs/2]);
    cout<<fixed<<setprecision(10)<<ans<<endl;
}void probC(){
    int i,j,l;
}void probD(){
    int i,j,l;
}void probF(){
    int i,j,l;
}void probG(){
    int i,j,l;
}void probH(){
    int i,j,l;
}void probI(){
    int i,j,l;
}void probJ(){
    int i,j,l;
}void probK(){
    int i,j,l;
}void probL(){
    int i,j,l;
}
i32 main(){
    fast;
    // int tc; cin>>tc;
    // while(tc--)f();
    probB();
    return 0;
}