(h,w,sx,sy,n),*e=[[*map(int,s.split())]for s in open(0)]
sx-=1;sy-=1
INF=1<<60
s=[0]+[-INF]*n
e=[(sx,sy,0)]+[(x-1,y-1,c)for x,y,c in e]
for i in range(1,n+1):
  x,y,c=e[i]
  bx,by,_=e[i-1]
  if i>1:
    s[i]=s[i-2]+c
  if bx==x or by==y or abs(bx-x)==abs(by-y):
    s[i]=max(s[i],s[i-1]+c)
print(max(s))