//#pragma GCC optimize("Ofast")
//#pragma GCC optimize("unroll-loops")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using db = double;
using ld = long double;
template <typename T> using V = vector<T>;
template <typename T> using VV = vector<vector<T>>;
#define fs first
#define sc second
#define pb push_back
#define mp make_pair
#define mt make_tuple
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound
#define all(v) (v).begin(), (v).end()
#define siz(v) (ll)(v).size()
#define rep(i, a, n) for(ll i = a; i < (ll)(n); ++i)
#define repr(i, a, n) for(ll i = n - 1; (ll)a <= i; --i)
#define ENDL '\n'
typedef pair<int, int> Pi;
typedef pair<ll, ll> PL;
constexpr ll mod = 1000000007;
constexpr ll INF = 1000000099;
constexpr ll LINF = (ll)(1e18 + 99);
const vector<ll> dx = {-1, 1, 0, 0}, dy = {0, 0, -1, 1};
template <typename T, typename U> inline bool chmin(T& t, const U& u) {
  if(t > u) {
    t = u;
    return 1;
  }
  return 0;
}
template <typename T, typename U> inline bool chmax(T& t, const U& u) {
  if(t < u) {
    t = u;
    return 1;
  }
  return 0;
}
template <typename T> inline T gcd(T a, T b) { return b ? gcd(b, a % b) : a; }

template <typename T, typename Y> inline T mpow(T a, Y n) {
  T res = 1;
  for(; n; n >>= 1) {
    if(n & 1) res = res * a;
    a = a * a;
  }
  return res;
}

template <typename T, typename Y>
ostream& operator<<(ostream& os, const pair<T, Y>& p) {
  return os << "{" << p.fs << "," << p.sc << "}";
}
template <typename T> ostream& operator<<(ostream& os, const V<T>& v) {
  os << "{";
  for(auto e : v) os << e << ",";
  return os << "}";
}
template <typename... Args> void debug(Args&... args) {
  for(auto const& x : {args...}) { cerr << x << ' '; }
  cerr << ENDL;
}

ll n, a, b, c, d, x;

signed main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(20);
    cin >> x >> n;
    if(x>=n){
      cout<<x-n<<ENDL;
      return 0;
    }
    a=d=1;
    b=c=INF;

    using Pa = pair<ll, ll>;
    map<ll, ll> D;  //----------------
    priority_queue<Pa, vector<Pa>, greater<Pa>> q;
    D[n] = 0;
    q.emplace(D[n], n);  //最短距離、ゴール頂点番号
    D[x] = LINF;

    ll ans=LINF;

    while(!q.empty()) {
      ll spath = q.top().first;
      ll v = q.top().second;
      chmin(ans,D[v]+abs(x-v));
      q.pop();

      if(D.count(v) && D[v] < spath) continue;
      D[v] = spath;
      rep(i, -4, 5) {
        if(v + i < 0) continue;

        if(abs(i) < 2 && (v + i) % 2 == 0 &&
           (!D.count((v + i) / 2) || D[(v + i) / 2] > D[v] + d * abs(i) + a)) {
          D[(v + i) / 2] = D[v] + d * abs(i) + a;
          q.emplace(D[(v + i) / 2], (v + i) / 2);
        }

        if(v + i == 0) { chmin(D[v + i], D[v] + d * abs(i)); }
      }
      if(log10(v) + log10(d) < 18.5) chmin(D[0], D[v] + v * d);
      //cerr<<v<<ENDL;
    }
    cout << ans << ENDL;
}
//! ( . _ . ) !
//CHECK overflow,vector_size,what to output?
#include<bits/stdc++.h>
using namespace std;
using P=pair<int,int>;
using ll=long long;
template<class T> using heapq = priority_queue<T,vector<T>,greater<T>>;
template<class T> bool chmax(T &a,const T b) {if (a<b) {a=b;return true;} else return false;} 
template<class T> bool chmin(T &a,const T b) {if (a>b) {a=b;return true;} else return false;} 
#define rep(i,n) for(int i=0; i<(n); i++)
#define srep(i,a,b) for(int i=(a); i<(b); i++)
#define rrep(i,n) for(int i=(n)-1;i>=0; i--)
#define srrep(i,a,b) for(int i=(b)-1; i>=(a); i--)
int main(){
    int n,m; cin >> n >> m;
    vector<int> A(n+1),W(m);
    vector<ll> even(n+1), odd(n+1);
    srep(i,1,n+1) cin >> A[i];
    for(int &i:W) cin >> i;
    sort(A.begin(),A.end());
    srep(i,1,n+1){
        if (i%2) odd[i]=A[i];
        else even[i]=A[i];
        odd[i]+=odd[i-1];
        even[i]+=even[i-1];
    }
    ll ans = 200000000000000L;
    for(int w:W){
        int ac = 0, wa = n+1;
        while(ac+1<wa){
            int mid = (ac+wa)/2;
            if (w<A[mid]) wa=mid;
            else ac = mid;
        }
        chmin(ans,odd[n]-2*odd[ac]-even[n]+2*even[ac]+((ac%2)?w:-w));
    }
    cout << ans << endl;
}