// This amazing code is by Eric Sunli Chen.
#include<bits/stdc++.h>
using namespace std;
template<typename T> bool get_int(T &x)
{
	char t=getchar();
	bool neg=false;
	x=0;
	for(; (t>'9'||t<'0')&&t!='-'&&t!=EOF; t=getchar());
	if(t=='-')neg=true,t=getchar();if(t==EOF)return false;
	for(; t<='9'&&t>='0'; t=getchar())x=x*10+t-'0';
	if(neg)x=-x;return true;
}
template<typename T> void print_int(T x)
{
	if(x<0)putchar('-'),x=-x;
	short a[20]= {},sz=0;
	while(x>0)a[sz++]=x%10,x/=10;
	if(sz==0)putchar('0');
	for(int i=sz-1; i>=0; i--)putchar('0'+a[i]);
}
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define get1(a) get_int(a)
#define get2(a,b) (get1(a)&&get1(b))
#define get3(a,b,c) (get1(a)&&get2(b,c))
#define printendl(a) print_int(a),puts("")
typedef long long LL;
typedef unsigned long long uLL;
typedef pair<int,int> pii;
const int inf=0x3f3f3f3f;
const LL Linf=1ll<<61;
const double pi=acos(-1.0);

const int maxn=100111;
int n,s,x[maxn];
LL p[maxn],ans;

int calc(int l,int r)
{
	if(x[r]<s)
	{
		ans+=s-x[l];
		return l;
	}
	if(x[l]>s)
	{
		ans+=x[r]-s;
		return r;
	}
	if(p[l]>=p[r])
	{
		p[l]+=p[r];
		ans+=x[r]-x[calc(l,r-1)];
		return r;
	}
	else
	{
		p[r]+=p[l];
		ans+=x[calc(l+1,r)]-x[l];
		return l;
	}
}

int main()
{
	get2(n,s);
	for(int i=1;i<=n;i++)get2(x[i],p[i]);
	calc(1,n);
	printendl(ans);
	return 0;
}
#include <bits/stdc++.h>
#define ll long long
#define N 1000100
ll n,s,ans,x[N],p[N];
using namespace std;
int main(){
    scanf("%lld%lld",&n,&s);
    for (ll i=1;i<=n;i++) scanf("%lld%lld",&x[i],&p[i]);
    for (ll l=1,r=n;l<=r;){
        if (x[l]>=s){ans+=x[r]-s; break;}//所有人都在一边直接开过去
        if (x[r]<=s){ans+=s-x[l]; break;}
        ans+=x[r]-x[l]; //每次来回开一趟
        if (p[l]>=p[r])
            while (l<r && p[l]>=p[r]) p[l]+=p[r],r--;//相同往左开
        else while (l<r && p[l]<p[r]) p[r]+=p[l],l++;
    }
    printf("%lld\n",ans);
    return 0;
}