#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pi pair<int,int>
#define pb push_back
const int maxn = 1e5 + 5;
bool rpaired[maxn];
bool bpaired[maxn];
ll min_total_length(vector<int> r, vector<int> b){
//for each point calculate the closest one
//pair all the closest ones first
ll ans = 0;
int n = r.size();
int m = b.size();
if( n <m){
set<int> bset(b.begin(), b.end());
for(int i =0; i<n; i++){
auto left = lower_bound(bset.begin(), bset.end(), r[i]);
bool canleft = left != bset.begin();
if(canleft)
left = prev(left);
auto right = upper_bound(bset.begin(), bset.end(), r[i]);
bool canright = right != bset.end();
if(canleft && canright){
if( r[i] - *left <= *right - r[i]){
ans+= r[i] - *left;
bset.erase(left);
}
else{
ans+= *right - r[i];
bset.erase(right);
}
}
else if(canleft){
ans+= r[i] - *left;
bset.erase(left);
}
else {
ans+= *right - r[i];
bset.erase(right);
}
}
for(int bpoint : bset){
auto left = lower_bound(r.begin(), r.end(), bpoint);
bool canleft = left != r.begin();
if(canleft)
left = prev(left);
auto right = upper_bound(r.begin(), r.end(), bpoint);
bool canright = right != r.end();
if(canleft && canright){
if( bpoint - *left <= *right -bpoint){
ans+= bpoint - *left;
}
else{
ans+= *right - bpoint;
}
}
else if(canleft){
ans+= bpoint - *left;
}
else {
ans+= *right - bpoint;
}
}
}
else{
set<int> rset(r.begin(), r.end());
for(int i =0; i<m; i++){
auto left = lower_bound(rset.begin(), rset.end(), b[i]);
bool canleft = left != rset.begin();
if(canleft)
left = prev(left);
auto right = upper_bound(rset.begin(), rset.end(), b[i]);
bool canright = right != rset.end();
if(canleft && canright){
if( b[i] - *left <= *right - b[i]){
ans+= b[i] - *left;
rset.erase(left);
}
else{
ans+= *right - b[i];
rset.erase(right);
}
}
else if(canleft){
ans+= b[i] - *left;
rset.erase(left);
}
else {
ans+= *right - b[i];
rset.erase(right);
}
}
for(int rpoint : rset){
auto left = lower_bound(b.begin(), b.end(), rpoint);
bool canleft = left != b.begin();
if(canleft)
left = prev(left);
auto right = upper_bound(b.begin(), b.end(), rpoint);
bool canright = right != b.end();
if(canleft && canright){
if( rpoint - *left <= *right -rpoint){
ans+= rpoint - *left;
}
else{
ans+= *right - rpoint;
}
}
else if(canleft){
ans+= rpoint - *left;
}
else {
ans+= *right - rpoint;
}
}
}
return ans;
}
/*
int main(){
int n, m; cin >> n >> m;
vector<int> r(n), b(m);
for(int i =0; i<n;i++) cin >> r[i];
for(int i = 0; i<m;i++) cin >> b[i];
cout << min_total_length(r, b)<<endl;
}
*/
