import numpy as np

stdin = np.fromstring(open(0).read(), np.int64, sep=' ')
N = stdin[0]
XL = stdin[1:].reshape(-1, 2).T
x = XL[0]
l = XL[1]
arg = np.argsort(x)
x = x[arg]
l = l[arg]
xleft = x - l
xright = x + l

count = 0
i = 0
while i < N - 1:
    for j in range(i + 1, N):
        if xright[i] > xright[j]:
            count += 1
            i += 1
            break
        elif xright[i] > xleft[j]:
            count += 1
            j = j + 1
        else:
            i = j
            break
    else:
        i = N - 1

print(N - count)