import sys
#input = sys.stdin.readline
input = sys.stdin.buffer.readline
from heapq import heapify, heappop, heappush

def main():
    N,M,X = map(int,input().split())
    A = []; B = []
    not_used = []; used = []
    for _ in range(N):
        a,b = map(int,input().split())
        A.append(a)
        B.append(b)
        heappush(not_used,(-a,b)) #値、組
    K = int(input())
    C = list(map(int,input().split()))
    dic = {}
    for c in C:
        if c in dic:
            dic[c] += 1
        else:
            dic[c] = 1
    L = []
    used_group = set([])
    score = 0
    ans = 0
    for i in range(N):
        if used:
            a,b = heappop(used)
            val_used_group = (-a,b)
        else:
            val_used_group = (0,0) #dummy
        
        val_not_group = (0,0) #dummy
        while not_used:
            a,b = heappop(not_used)
            a *= -1 #正に値に直す
            #print(a,b)
            #print("VAL",val_used_group)
            if b not in used_group:
                val_not_group = (a,b)
                break
            else:
                if val_used_group[0] > a: #既に出した値が同じ組中で最高
                    heappush(used,(-a,b))
                else:
                    temp = (a,b)
                    val_used_group, temp = temp, val_used_group
                    a,b = temp
                    heappush(used,(-a,b))
        #print(val_used_group,val_not_group)
        if val_used_group == (0,0):
            L.append(val_not_group)
            used_group.add(val_not_group[1])
            score += val_not_group[0] + X
        elif val_not_group == (0,0):
            L.append(val_used_group)
            used_group.add(val_used_group[1])
            score += val_used_group[0]
        else:
            score_used = score + val_used_group[0]
            socre_not = score + val_not_group[0] + X #1組増えるので
            if score_used > socre_not: #使用済みのグループを使う。
                score = score_used
                L.append(val_used_group)
                used_group.add(val_used_group[1])
                heappush(not_used,(-val_not_group[0],val_not_group[1]))
            else:
                score = socre_not
                L.append(val_not_group)
                used_group.add(val_not_group[1])
                heappush(used, (-val_used_group[0],val_used_group[1]))
        #print(score)
        if i+1 in dic:
            ans += score*dic[i+1]
    #print(L)
    print(ans)


if __name__ == '__main__':
    main()