#include <bits/stdc++.h>
using namespace std;
const int MaxN = 5010;
int N, l, r;
long long ans;
int main() {
  scanf("%d%d", &N, &l);
  r = l;
  for (int i = 1, __end = N; i <= __end; ++i) {
    int u, v;
    scanf("%d%d", &u, &v);
    if (max(l, u) <= min(r, v)) {
      l = max(l, u);
      r = min(r, v);
    } else if (v < l) {
      ans += l - v;
      r = l;
      l = v;
    } else if (r < u) {
      ans += u - r;
      l = r;
      r = u;
    }
  }
  cout << ans << endl;
  return 0;
}
