#pragma comment(linker, "/STACK:1024000000,1024000000")

#include<cstdio>

#include<cstring>

#include<cmath>

#include<algorithm>

#include<vector>

#include<map>

#include<set>

#include<queue>

#include<stack>

#include<iostream>

using namespace std;

typedef long long LL;

const double pi=acos(-1.0),eps=1e-;

void File()

{

    freopen("D:\\in.txt","r",stdin);

    freopen("D:\\out.txt","w",stdout);

}

template <class T>

inline void read(T &x)

{

    char c = getchar(); x = ;while(!isdigit(c)) c = getchar();

    while(isdigit(c)) { x = x *  + c - ''; c = getchar();  }

}

const int maxn=;

int n,a[maxn];

char s[maxn];

int main()

{

    scanf("%d",&n); scanf("%s",s);

    for(int i=;i<n;i++) scanf("%d",&a[i]);

    int ans=0x7FFFFFFF;

    for(int i=;i<n-;i++)

        if(s[i]=='R'&&s[i+]=='L') ans=min(ans,(a[i+]-a[i])/);

    if(ans==0x7FFFFFFF) printf("-1\n");

    else printf("%d\n",ans);

    return ;

}