#include <cstdio>

 #include <cstring>

 #include <algorithm>

 #include <set>

 #include <queue>

 #define maxn 50010

 #define inc(i,j,k) for(int i=j;i<=k;i++)

 using namespace std;

 inline int read(){

     char ch=getchar(); int f=,x=;

     while(ch<''||ch>''){if(ch=='-')f=-; ch=getchar();}

     while(ch>=''&&ch<='')x=x*+ch-'',ch=getchar();

     return f*x;

 }

 int x[maxn],y[maxn],n,t,dis[maxn]; queue<int>q;

 struct nd{

     int x,y,id;

     bool operator < (const nd &a)const{return x!=a.x?x<a.x:y<a.y;}

 };

 set<nd>st;

 int main(){

     n=read(); t=read(); inc(i,,n)x[i]=read(),y[i]=read(),st.insert((nd){x[i],y[i],i});

     q.push(); dis[]=;

     while(!q.empty()){

         int z=q.front(); q.pop();

         inc(i,-,)inc(j,-,){

             set<nd>::iterator a=st.find((nd){x[z]+i,y[z]+j,});

             if(a!=st.end()){

                 dis[a->id]=dis[z]+; q.push(a->id);

                 if(a->y==t){printf("%d",dis[a->id]); return ;} st.erase(a);

             }

         }

     }

     printf("-1"); return ;

 }