gx,gy,N,F = map(int,input().split())
x = [0 for i in range(N)]
y = [0 for i in range(N)]
c = [0 for i in range(N)]
for i in range(N):
	x[i],y[i],c[i] = map(int,input().split())
ans = 10**9+7
q = [(0,0,0,0)]
while len(q) > 0:
	p = q.pop(0)
	if p[0] == gx and p[1] == gy:
		ans = min(ans,p[2])
		continue;
	for i in range(N):
		if p[3] >> i & 1:
			continue
		if p[0]+x[i]<=gx and p[1]+y[i]<=gy and p[2]+c[i] < ans:
			q.append((p[0]+x[i],p[1]+y[i],p[2]+c[i],p[3]|(1<<i)))
	if p[0]+1 <= gx:
		q.append((p[0]+1,p[1],p[2]+F,p[3]))
	if p[1]+1 <= gy:
		q.append((p[0],p[1]+1,p[2]+F,p[3]))
print(ans)