#include <bits/stdc++.h>
using namespace std;
struct dd
{
    int x;
    double viteza;
};
dd v[10005];
const double eps=1.e-14;
bool cmp(double a ,double b)
{
    if(a-b<=eps)return 1;
    return 0;
}
double timp[10005];
double r;
double sol(dd a,dd b)
{
    if(fabs(a.x-b.x)<=2*r)
    {
        return 0;
    }
    if(b.x-a.x<=-eps)
    {
        dd m;
        m=a;
        a=b;
        b=m;
    }
    if(b.x-a.x>=eps)
    {
        if(b.viteza>0&&a.viteza<0)return 0;
        if(b.viteza>0&&b.viteza-a.viteza>0)return 0;
        if(b.viteza<0&&a.viteza<0&&b.viteza-a.viteza<0)return 0;
            return 1.0*(b.x-a.x-2*r)/(a.viteza-b.viteza);

    }
}
int main()
{
    freopen("bomba.in","r",stdin);
    freopen("bomba.out","w",stdout);
    int n;
    int i,j;
    scanf("%d%lf",&n,&r);
    for(i=1;i<=n;i++)
        scanf("%d%lf",&v[i].x,&v[i].viteza);
        int cnt=0;
    for(i=1;i<=n;i++)
        for(j=i+1;j<=n;j++)
        timp[++cnt]=sol(v[i],v[j]);
    for(i=1;i<=cnt;i++)
    printf("%lf\n",timp[i]);
    return 0;
}