#include <bits/stdc++.h>
#include <random>

using namespace std;

typedef unsigned long long ull;
typedef long long ll;
typedef double ld;
//#define ll __int128
#define int ll
//#define int ll
//#define char ll
typedef vector<char> vc;
typedef vector<vc> vvc;
typedef vector<vvc> vvvc;
typedef pair<int, int> pii;
typedef pair<pii, pii> piii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<pii> vpi;
typedef vector< vi > vvi;
typedef vector< vvi > vvvi;
typedef vector<short> vs;
typedef vector<vs> vvs;
typedef vector<vvs> vvvs;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<vvl> vvvl;
typedef vector<ld> vld;
typedef vector<vld> vvld;
typedef vector<vvld> vvvld;
typedef vector<string> vst;
typedef vector<vst> vvst;
typedef pair<ld, ld> pld;

#define inmin(a, b) a = min(a, (b))
#define inmax(a, b) a = max(a, (b))
#define ALL(a) a.begin(),a.end()
#define RALL(a) a.rbegin(),a.rend()
#define sqr(x) ((x) * (x))
#define fori(i, n) for(int i = 0; i < int(n); ++i)
#define SZ(a) ((int)((a).size()))
#define triple(T) tuple<T, T, T>
#define quad(T) tuple<T, T, T, T>
#define watch(x) cerr << (#x) << " = " << (x) << endl;

#ifdef MAX_HOME
#define cerr cout
#else
#define cerr if (false) cerr
#endif

const double PI = 2 * acos(0.0);
#define rand shittttty_shit
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng_64(chrono::steady_clock::now().time_since_epoch().count());

const string DIGITS = "0123456789";
const string ALPH = "abcdefghijklmnopqrstuvwxyz";


template <class T0, class T1>
inline ostream & operator << (ostream &out, pair<T0, T1> &a) {
    return out << "{" << a.first << ", " << a.second << "}";
}

template <class T0, class T1>
inline istream & operator >> (istream &in, pair<T0, T1> &a) {
    return in >> a.first >> a.second;
}

template <class T0, class T1, class T2>
inline ostream & operator << (ostream &out, tuple<T0, T1, T2> &a) {
    return out << "{" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a) << "}";
}

template <class T0, class T1, class T2, class T3>
inline ostream & operator << (ostream &out, tuple<T0, T1, T2, T3> &a) {
    return out << "{" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a) << ", " <<  get<3>(a) << "}";
}

template<class T>
inline ostream & operator << (ostream &out, vector<T> &a) {
    out << "[";
    fori (i, a.size())
        out << a[i] << vector<string>{", ", "]  "}[i + 1 == a.size()];
    return out;
}


void smain();



signed main() {
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
#ifdef MAX_HOME
    freopen("input.txt", "r", stdin);
    clock_t start = clock();
#endif
    cout << setprecision(12) << fixed;
    smain();
#ifdef MAX_HOME
    cout << "\n\n\n\nTOTAL EXECUTION TIME: " << float( clock () - start ) /  CLOCKS_PER_SEC << endl;
#endif
    return 0;
}
const int N = 1e5 + 10;

int x[N], p[N];


void smain() {

    int n, s;
    cin >> n >> s;
    vi a, b;
    fori (i, n) {
        cin >> x[i] >> p[i];
        x[i] -= s;
        if (x[i] < 0)
            a.push_back(i);
        else
            b.push_back(i);
//        cerr << x[i] << ' ';
    }
//    cerr << '\n';

    reverse(ALL(a));
    ll sum = 0;
    bool awin;
    ll ans = 0;
    ll coord;
    if (a.empty()) {
        cout << abs(x[b.back()]);
        return;
    }
    if (b.empty()) {
        cout << abs(x[a.back()]);
        return;
    }

    if (!(p[a.back()] >= p[b.back()])) {
        awin = true;
        coord = x[a.back()];
        sum = p[a.back()];
    } else {
        awin = false;
        coord = x[b.back()];
        sum = p[b.back()];
    }
    while (SZ(a) && SZ(b)) {
        if (awin) {
            if (sum >= p[b.back()]) {
                sum += p[b.back()];
                b.pop_back();
            } else {
                sum += p[b.back()];
                ans += abs(coord - x[b.back()]);
                coord = x[b.back()];
                a.pop_back();
                awin = false;
            }
        } else {
            if (sum > p[a.back()]) {
                sum += p[a.back()];
                a.pop_back();
            } else {
                sum += p[a.back()];
                ans += abs(coord - x[a.back()]);
                coord = x[a.back()];
                b.pop_back();
                awin = true;
            }
        }
    }
    ans += abs(coord);

    cout << ans;
}

Measured memory_bytes: 3064