#include<bits/stdc++.h>
using namespace std;
#define int long long
const int N=2e5+10;
char s[N];int x[N],a[N],b[N],l,r;
signed main()
{
	int n,t;scanf("%lld%lld%s",&n,&t,s+1);
	for(int i=1;i<=n;i++)
	{
		scanf("%lld",&x[i]);
		if(s[i]=='1')a[++l]=x[i];
		else b[++r]=x[i];
	}
	int ans=0;
	sort(b+1,b+r+1);
	for(int i=1;i<=l;i++)
	{
		int id1=upper_bound(b+1,b+r+1,a[i]+t*2)-b-1;
		int id2=lower_bound(b+1,b+r+1,a[i])-b;
		ans+=id1-id2+1;
	}
	printf("%lld\n",ans);
	return 0;
}