//Author:xht37
#include <bits/stdc++.h>

#define ui unsigned int
#define ll long long
#define ul unsigned ll
#define ld long double

#define pi pair <int, int>
#define fi first
#define se second
#define mp make_pair

#define ls (p << 1)
#define rs (ls | 1)
#define md ((t[p].l + t[p].r) >> 1)

#define vi vector <int>
#define pb push_back
#define pq priority_queue

#define dbg(x) cerr << #x" = " << x << endl
#define debug(...) fprintf(stderr, __VA_ARGS__)

#define fl(x) freopen(x".in", "r", stdin), freopen(x".out", "w", stdout)

using namespace std;

namespace io {
	const int SI = 1 << 21 | 1;
	char IB[SI], *IS, *IT, OB[SI], *OS = OB, *OT = OS + SI - 1, c, ch[100];
	int f, t;
	#define gc() (IS == IT ? (IT = (IS = IB) + fread(IB, 1, SI, stdin), IS == IT ? EOF : *IS++) : *IS++)
	inline void flush() {
		fwrite(OB, 1, OS - OB, stdout), OS = OB;
	}
	inline void pc(char x) {
		*OS++ = x;
		if (OS == OT) flush();
	}

	template <class I>
	inline void rd(I &x) {
		for (f = 1, c = gc(); c < '0' || c > '9'; c = gc()) if (c == '-') f = -1;
		for (x = 0; c >= '0' && c <= '9'; x = (x << 3) + (x << 1) + (c & 15), c = gc());
		x *= f;
	}
	template <class I>
	inline void rd(I &x, I &y) {
		rd(x), rd(y);
	}
	template <class I>
	inline void rd(I &x, I &y, I &z) {
		rd(x), rd(y), rd(z);
	}
	template <class I>
	inline void rda(I *a, int n) {
		for (int i = 1; i <= n; i++) rd(a[i]);
	}
	inline void rdc(char &c) {
		for (c = gc(); c < 33 || c > 126; c = gc());
	}
	inline void rds(char *s, int &n) {
		for (c = gc(); c < 33 || c > 126; c = gc());
		for (n = 0; c >= 33 && c <= 126; s[++n] = c, c = gc());
		s[n+1] = '\0';
	}
	inline void rds(string &s) {
		for (c = gc(); c < 33 || c > 126; c = gc());
		for (s.clear(); c >= 33 && c <= 126; s.pb(c), c = gc());
	}

	template <class I>
	inline void print(I x, char k = '\n') {
		if (!x) pc('0');
		if (x < 0) pc('-'), x = -x;
		while (x) ch[++t] = x % 10 + '0', x /= 10;
		while (t) pc(ch[t--]);
		pc(k);
	}
	template <class I>
	inline void print(I x, I y) {
		print(x, ' '), print(y);
	}
	template <class I>
	inline void print(I x, I y, I z) {
		print(x, ' '), print(y, ' '), print(z);
	}
	template <class I>
	inline void printa(I *a, int n) {
		for (int i = 1; i <= n; i++) print(a[i], " \n"[i==n]);
	}
	inline void printc(char c) {
		pc(c);
	}
	inline void prints(char *s, int n) {
		for (int i = 1; i <= n; i++) pc(s[i]);
		pc('\n');
	}
	inline void prints(string s) {
		int n = s.length();
		while (t < n) pc(s[t++]);
		pc('\n'), t = 0;
	}
	struct Flush {
		~Flush() {
			flush();
		}
	} flusher;
}
using io::rd;
using io::rda;
using io::rdc;
using io::rds;
using io::print;
using io::printa;
using io::printc;
using io::prints;

const int N = 1e5 + 7;
int n;
ll s, x[N], p[N];

ll f(int l, int r, int o) {
	if (s < x[l] || x[r] < s) return abs(s - x[o]);
	if (p[l] >= p[r]) return p[l] += p[r], f(l, r - 1, l) + abs(x[l] - x[o]);
	return p[r] += p[l], f(l + 1, r, r) + abs(x[r] - x[o]);
}

int main() {
	rd(n), rd(s);
	for (int i = 1; i <= n; i++) rd(x[i], p[i]);
	print(f(1, n, s < x[1] ? n : x[n] < s ? 1 : p[1] >= p[n] ? n : 1));
	return 0;
}
#include <bits/stdc++.h>
#define ll long long
#define maxn 100005 /*rem*/
#define mod 998244353
#define db double
#define vi vector<int>
#define pb push_back
#define mp make_pair
#define pi pair<int, int>
#define fi first
#define se second
using namespace std;
ll ksm(ll a, ll b) {
   if (!b) return 1;
   ll ns = ksm(a, b >> 1);
   ns = ns * ns % mod;
   if (b & 1) ns = ns * a % mod;
   return ns;
}
int n, s;
ll ans;
int x[maxn];
ll p[maxn];
ll ttm[maxn];
int ls[maxn], pp[maxn];
void caltm(int a) {
	if (!ls[a]) return ;
	else if (ttm[a]) return ;
	else caltm(ls[a]), ttm[a] = ttm[ls[a]] + pp[a];
}
int main() {
	cin >> n >> s;
	for (int i = 1; i <= n; i++)
		scanf("%d%d", &x[i], &p[i]);
	int l = 1, r = n;
	while (1) {
		if (s <= x[l] || s >= x[r]) {
			for (int i = l; i <= r; i++)
				ttm[i] = abs(s - x[i]);
			break;
		}
		if (p[l] >= p[r]) {
			ls[r] = l, pp[r] = x[r] - x[l];
			p[l] += p[r], r--;
		}
		else {
			ls[l] = r, pp[l] = x[r] - x[l];
			p[r] += p[l], l++;
		}
	}
	for (int i = 1; i <= n; i++)
		caltm(i), ans = max(ans, ttm[i]);//, cout << ttm[i] << ' ' << ls[i] << ' ' << pp[i] << endl;
	cout << ans << endl;
	return 0;
}
