with open("input.txt") as f:
lines = [int(i) for i in f.readlines()]
hits = 0
winsize = 3
last = sum([lines[0], lines[1], lines[2]])
for i in range(3, len(lines)):
now = last - lines[i - 3] + lines[i]
if now > last:
hits += 1
print(hits)