#include <iostream>
#include <vector>
#include <algorithm>
#include <math.h>
#include <set>
#define forr(i,a,b,c) for(int i=a;i<b;i+=c)
#define fort(i,a,b) forr(i,a,b,1)
#define forn(i,n) fort(i,1,n)
#define fori(i,n) fort(i,0,n)
#define forrb(i,a,b,c) for(int i=b-1;i>=a;i-=c)
#define fortb(i,a,b) forrb(i,a,b,1)
#define fornb(i,n) fortb(i,1,n)
#define forib(i,n) fortb(i,0,n)
using namespace std;
#define into(x) cin >> x;
typedef vector<int> veci;
typedef long long lol;
typedef pair<lol,lol> point;
#define def(x) lol x; into(x)
#define logn 20
int main() {
ios::sync_with_stdio();
def(n) def(m)
vector<point> x,y;
fori(i, n) {
def(a) def(b)
x.push_back({ a,b });
}
fori(i, m) {
def(a)
y.push_back({ a,i });
}
sort(y.begin(), y.end());
vector<veci> arr(logn, veci(m+1));
veci xx(m);
set<point> r;
forib(i, m) {
int ii = y[i].second+1;
int sum = 0;
fori(j, logn) {
if (ii % 2 == 1) {
sum += arr[j][ii];
ii++;
}
ii /= 2;
}
xx[i] = sum;
ii = y[i].second;
fori(j, logn) {
arr[j][ii]++;
ii /= 2;
}
}
fori(i, m) {
arr[0][i] = y[i].second;
}
forn(j, logn) {
fori(i, (m / 2) + 1) {
arr[j][i] = max(arr[j - 1][2 * i], arr[j - 1][2 * i + 1]);
}
}
veci op(m);
fori(i, m) {
op[y[i].second] = i;
}
lol sum = 0;
fori(i, n) {
int low = 0, high = m;
int small = min(x[i].first, x[i].second);
while (low < high) {
int mid = (low + high) / 2;
if (y[mid].first < small) {
low = mid + 1;
}
else {
high = mid;
}
}
int lower = low;
low = -1, high = m - 1;
int big = max(x[i].first, x[i].second);
while (low < high) {
int mid = (low + high+1) / 2;
if (y[mid].first >= big) {
high = mid - 1;
}
else {
low = mid;
}
}
int higer = high;
int best = -1;
fori(j, logn) {
if (lower > higer) {
break;
}
if (lower % 2 == 1) {
best = max(best,arr[j][lower]);
lower++;
}
if (higer % 2 == 0) {
best = max(best, arr[j][higer]);
higer--;
if (higer < 0) {
break;
}
}
lower /= 2;
higer /= 2;
}
if (best == -1) {
int num = m - lower;
if (num % 2 == 1) {
sum += x[i].second;
}
else {
sum += x[i].first;
}
}
else {
int num = xx[op[best]];
if (num % 2 == 1) {
sum += small;
}
else {
sum += big;
}
}
}
cout << sum << endl;
return 0 ;
}
