#include <bits/stdc++.h>
using namespace std;

constexpr int mod = 998244353;

template <typename T>
struct BinaryIndexedTree {
    int N;
    vector<T>bit;
    BinaryIndexedTree(){}
    BinaryIndexedTree(int x) {
        N = x;
        bit.resize(x+1);
    }
    void add(int x,T y) {
        while(x <= N) {
            bit[x] += y;
            if(bit[x] >= mod) {
                bit[x] -= mod;
            }
            x += x&-x;
        }
    }
    T sum(int x) {
        T res = 0;
        while(x) {
            res += bit[x];
            if(res >= mod) {
                res -= mod;
            }
            x -= x&-x;
        }
        return res;
    }
    inline T sum(int l, int r) {//[l,r]
        int res = sum(r)-sum(l-1);
        if(res < 0) res += mod;
        return res;
    }
    inline T operator[](int k) {
        return sum(k)-sum(k-1);
    }
};

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int N;
    cin >> N;
    vector<int>X(N),Y(N);
    for(int i = 0; i < N; i++) {
        cin >> X[i] >> Y[i];
        X[i] = X[i]+Y[i];
        Y[i] = X[i]-Y[i]*2;
    }
    if(X[0] > X[N-1]) {
        for(int i = 0; i < N; i++) {
            X[i] = -X[i];
        }
    }
    if(Y[0] > Y[N-1]) {
        for(int i = 0; i < N; i++) {
            Y[i] = -Y[i];
        }
    }
    vector<array<int,3>>tmp(N);
    vector<int>cmp(N);
    for(int i = 0; i < N; i++) {
        tmp[i][0] = X[i],tmp[i][1] = Y[i],tmp[i][2] = i;
        cmp[i] = Y[i];
    }
    sort(tmp.begin(),tmp.end());
    sort(cmp.begin(),cmp.end());
    cmp.erase(unique(cmp.begin(),cmp.end()),cmp.end());
    BinaryIndexedTree<int>bit(cmp.size());
    for(int i = 0; i < N; i++) {
        int it = lower_bound(cmp.begin(),cmp.end(),tmp[i][1])-cmp.begin();
        if(tmp[i][2] == N-1) {
            cout << bit.sum(1,it+1) << endl;
            return 0;
        }
        if(tmp[i][2] == 0) {
            bit.add(it+1,1);
        }
        else {
            bit.add(it+1,bit.sum(1,it+1));
        }
    }
}