def forClient(curClient, sumMinus, used):
    for j in range(0, m):
        if j not in used and clientToClient[curClient][j]>0:
            temp = p-sumMinus-clientToClient[curClient][j]
            if sumMinus>=p:
                continue;
            minToClient[j] = minToClient[j] - temp;
            used.append(j);
            forClient(j, sumMinus+clientToClient[curClient][j], used)

m, n, p, k = [int(x) for x in input().split()]

driverToClient = [[0 for x in range(m)] for y in range(n)];

for i in range(0, int(input())):
    driver, client, r = [int(x) for x in input().split()]
    driverToClient[driver][client] = r;
#print(driverToClient);

clientToClient = [[0 for x in range(m)] for y in range(m)];
for i in range(0, int(input())):
    client1, client2, r = [int(x) for x in input().split()]
    clientToClient[client1][client2] = r;
#print(clientToClient);

minToClient = [k for x in range(m)];

for i in range(0,n):
    used = [];
    for j in range(0,m):
        if driverToClient[i][j]==0:
            continue;
        minToClient[j] = minToClient[j] - (p-driverToClient[i][j]);
        used.append(j);
        forClient(j,driverToClient[i][j], used);


print(min(minToClient))