#include <bits/stdc++.h>
using namespace std;
const int MAXN = 2 * 100100, MAXK = 2 * 100100, MAXA = 1e9 + 1e2;
int n, k, a[MAXN], b[MAXN];
long long ans = 0;
struct no
{
int v;
no *l, *r;
no(int v = 0) : v(v), l(nullptr), r(nullptr)
{}
};
inline int getv(no *n) { return (n ? n->v : 0); }
no *upd(no *n, int (*joinFunc)(int, int), int pos, int val = 1, int beg = 1, int end = MAXA)
{
if(beg == end)
return new no(joinFunc(getv(n), val));
no *ans = (n ? new no(*n) : new no());
int mid = (beg + end) >> 1;
if(pos <= mid)
ans->l = upd(ans->l, joinFunc, pos, val, beg, mid);
else
ans->r = upd(ans->r, joinFunc, pos, val, mid + 1, end);
ans->v = joinFunc(getv(ans->l), getv(ans->r));
return ans;
}
int get(no* n, int (*joinFunc)(int, int), int a, int b, int beg = 1, int end = MAXA)
{
if(!n || b < beg || end < a)
return 0;
if(a <= beg && end <= b)
return getv(n);
int mid = (beg + end) >> 1;
return joinFunc(get(n->l, joinFunc, a, b, beg, mid), get(n->r, joinFunc, a, b, mid + 1, end));
}
no *pseg[MAXK], *seg;
int main()
{
pseg[0] = seg = nullptr;
scanf("%d %d", &n, &k);
for(int i = 1; i <= n; ++i)
scanf("%d %d", &a[i], &b[i]);
for(int i = 1, t; i <= k; ++i)
scanf("%d", &t), pseg[i] = upd(pseg[i - 1], [](int x, int y){ return x + y; }, t), seg = upd(seg, [](int x, int y){ return max(x, y); }, t, i);
for(int i = 1, swaps, j; i <= n; ++i)
{
j = get(seg, [](int x, int y){ return max(x, y); }, min(a[i], b[i]), max(a[i], b[i]) - 1), swaps = 0;
if(j)
swaps += (a[i] < b[i]);
swaps += get(pseg[k], [](int x, int y){ return x + y; }, max(a[i], b[i]) - 1, MAXA) - get(pseg[j], [](int x, int y){ return x + y; }, max(a[i], b[i]) - 1, MAXA);
ans += (swaps % 2 ? b[i] : a[i]);
}
printf("%lld\n", ans);
}
