with open("input.txt") as f:
    lines = [int(i) for i in f.readlines()]


hits = 0
window = lines[0:3]

for line in lines[3:]:
    oldwindow = list(window)
    window.pop(0)
    window.append(line)

    if sum(oldwindow) < sum(window):
        hits += 1


print(hits)


# 5m41s