N = int(input())
s = [0]*N
t = [0]*N
for i in range(N):
    s[i],t[i] = input().split()
s = [int(x) for x in s]
t = [int(x) for x in t]
def sel(a,b):
    u = []
    c = 0
    for i in range(len(a)-3):
        if abs(a[i+1] - a[i]) < b[i+1] + b[i]:
            c = c + 1
            a.pop(i)
            b.pop(i)
            a1 = a
            b1 = b
            sel(a1,b1)
            c = 0
    if c == 0:
        u.append(len(a))
    return u
u1 = sorted(sel(s,t))
print(u1[-1])