#include<bits/stdc++.h>

 #define N 1050

 using namespace std;

 int n,l,m;

 const double pi=acos(-);

 struct P{

     int x,y;

     bool operator < (const P &b)const{

         return x==b.x?y<b.y:x<b.x;

     }

     P operator - (const P &b)const{

         return (P){x-b.x,y-b.y};

     }

 }a[N],s[N];

 double dis(P a,P b){

     return sqrt(1.0*(a.x-b.x)*(a.x-b.x)+1.0*(a.y-b.y)*(a.y-b.y));

 }

 int crs(P a,P b){return a.x*b.y-a.y*b.x;}

 void getbag(){

     m=;sort(a+,a++n);

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

         while(m>&&crs(a[i]-s[m-],s[m]-s[m-])>=)m--;

         s[++m]=a[i];

     }

     int now=m;

     for(int i=n-;i>=;i--){

         while(m>now&&crs(a[i]-s[m-],s[m]-s[m-])>=)m--;

         s[++m]=a[i];

     }

     if(n>)m--;

 }

 int main(){

     int cas;scanf("%d",&cas);

     while(cas--){

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

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

         scanf("%d%d",&a[i].x,&a[i].y);

         getbag();

         double ans=;

         for(int i=;i<m;i++)

         ans+=dis(s[i],s[i+]);

         ans+=dis(s[],s[m]);

         ans+=*pi*l;

         printf("%.0lf\n",ans);

         if(cas)puts("");

     }

     return ;

 }