#include <bits/stdc++.h>
#define ll long long
#define X first
#define Y second
#define MP make_pair
using namespace std;
const int N = 2e5 + 12;
int n, k, b[N], p[N], f[N];
pair<int, int> a[N];
void upd_f(int v, int val){
for(;v <= k;v |= v + 1)
f[v] += val;
}
int get_f(int v){
int val = 0;
for(;v >= 0;v = (v & (v + 1)) - 1)
val += f[v];
return val;
}
int t[N * 4];
void build(int v, int tl, int tr){
if(tl == tr){
t[v] = b[tl];
return;
}
int tm = (tl + tr) / 2;
build(v * 2, tl, tm), build(v * 2 + 1, tm + 1, tr);
t[v] = max(t[v * 2], t[v * 2 + 1]);
}
void upd(int v, int tl, int tr, int pos, int val){
if(tl > pos || pos > tr)
return;
if(tl == tr){
t[v] = val;
return;
}
int tm = (tl + tr) / 2;
upd(v * 2, tl, tm, pos, val), upd(v * 2 + 1, tm + 1, tr, pos, val);
t[v] = max(t[v * 2], t[v * 2 + 1]);
}
int rec(int v, int tl, int tr, int val){
if(tl == tr)
return tl;
int tm = (tl + tr) / 2;
if(t[v * 2 + 1] >= val)
return rec(v * 2 + 1, tm + 1, tr, val);
else if(t[v * 2] >= val)
return rec(v * 2, tl, tm, val);
return 0;
}
int main () {
scanf("%d %d", &n, &k);
for(int i = 1;i <= n;i++)
scanf("%d %d", &a[i].X, &a[i].Y);
for(int i = 1;i <= k;i++)
scanf("%d", &b[i]), p[i] = i;
sort(a + 1, a + n + 1, [](pair<int, int> x, pair<int, int> y){
return max(x.X, x.Y) > max(y.X, y.Y);
});
sort(p + 1, p + k + 1, [](int x, int y){
return b[x] > b[y];
});
build(1, 1, k);
int ptr = 1;
ll ans = 0;
for(int i = 1;i <= n;i++){
while(ptr <= k && b[p[ptr]] >= max(a[i].X, a[i].Y))
upd(1, 1, k, p[ptr], 0), upd_f(k - p[ptr] + 1, 1), ptr++;
int tmp = rec(1, 1, k, min(a[i].X, a[i].Y));
int cnt = get_f(k - tmp);
if(tmp != 0){
if(a[i].X < a[i].Y)
swap(a[i].X, a[i].Y);
}
if(cnt & 1)
ans += a[i].Y;
else
ans += a[i].X;
}
printf("%lld", ans);
}
