import math
import sys
from fractions import Fraction
from typing import List, Tuple


def int1(x: str, /): return int(x) - 1


def vi(): return list(map(int, input().split()))


def input(): return sys.stdin.readline().rstrip('\n')


def dbg(*args, **kwargs):
    print(*(repr(arg) for arg in args), *(f'{k}: {repr(v)}' for k, v in kwargs.items()),
          sep='; ', file=sys.stderr, flush=True)


def main():
    n = int(input())
    t, s = vi(), vi()
    cur = ans = 0
    for ti, si in zip(t, s):
        if cur <= si:
            cur = ti + si
            ans += 1
    return ans


def _start():
    ret = main()

    if ret is not None:
        if isinstance(ret, List) or isinstance(ret, Tuple):
            print(*ret)
        else:
            print(ret)


if __name__ == '__main__':
    _start()