h,w,x,y,n=map(int,input().split())
X=[]
DP=[-10**18,0]
for i in range(n):
    a,b,c=map(int,input().split())
    if a==x or b==y or abs(a-x)==abs(b-y):
        DP.append(DP[-1]+c)
    else:
        DP.append(max(DP[-1],DP[-2]+c))
    x,y=a,b
print(DP[-1])