#!/usr/bin/env python3
import sys

prev = None
mem = []
count = 0
i = 0
for l in sys.stdin:
    curr = int(l.strip())

    if len(mem) < 3:
        mem.append(curr)
        continue
    else:
        mem[i % 3] = curr
        i += 1

    s = sum(mem)
    if prev and s > prev:
        count += 1
    prev = s

print(count)