N = int(input())
P = 998244353
import sys
if N == 2:
    print(1)
    exit()
point = []
for _ in range(N):
    x,y = map(int,input().split())
    s = x + y
    t = y - x
    point.append((s,t))
s,t = point[0]
for i in range(N):
    x,y = point[i]
    point[i] = (x-s,y-t)
u,v = point[-1]
uu = 1
if u < 0:
    uu = -1
    u = -u
vv = 1
if v < 0:
    vv = -1
    v = -v
for i in range(N):
    x,y = point[i]
    point[i] = (x * uu,y * vv)
l = []
s = set()
for i in range(1,N-1):
    x,y = point[i]
    if 0 <= x <= u and 0 <= y <= v:
        l.append((x,y))
        s.add(y)
l.sort()
rD = sorted(s)
D = {v:i for i,v in enumerate(rD)}
n = len(D)
N = len(l)
bit = [0] * (n + 1)
def add(i,x):
    while i <= n:
        bit[i] += x
        i += i & -i
def fold(i):
    ans = 0
    while i > 0:
        ans = (ans + bit[i]) % P
        i -= i & -i
    return ans

for x,y in l:
    num = fold(D[y]+1)
    add(D[y]+1,num + 1)
ans = fold(n) + 1
print(ans % P)