C++

#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define sz(v) (v).size()
#define all(v) (v).begin(), (v).end()
#define pb(a) push_back(a)
#define pr(a,b) make_pair(a,b)
#define f first
#define s second

signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    int n, s; cin >> n >> s;
    map<int,ll> mp; mp[s] = 0;
    for (int i = 0; i < n; i++) {
        int l, r; cin >> l >> r;
        ll mnl = 1e18, mnr = 1e18;
        auto it = mp.lower_bound(l);
        while (it != mp.end() && it->f <= r) {
            mnl = min(mnl, it->s + it->f - l);
            mnr = min(mnr, it->s + r - it->f);
            ++it;
            mp.erase(prev(it));
        }
        mp[l] = mnl;
        mp[r] = mnr;
    }
    ll ans = 1e18;
    for (auto &[a, b]: mp) ans = min(ans, b);
    cout << ans << "\n";
}