#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <vector>
#include <iomanip>
#include <sstream>
#include <bitset>
#define ALL(x) (x).begin(), (x).end()
#define sz(a) int(a.size())
#define rep(i,x,n) for(int i=x;i<n;i++)
#define repd(i,x,n) for(int i=x;i<=n;i++)
#define pii pair<int,int>
#define pll pair<long long ,long long>
#define gbtb ios::sync_with_stdio(false),cin.tie(0),cout.tie(0)
#define MS0(X) memset((X), 0, sizeof((X)))
#define MSC0(X) memset((X), '\0', sizeof((X)))
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define eps 1e-6
#define chu(x) cout<<"["<<#x<<" "<<(x)<<"]"<<endl
#define du3(a,b,c) scanf("%d %d %d",&(a),&(b),&(c))
#define du2(a,b) scanf("%d %d",&(a),&(b))
#define du1(a) scanf("%d",&(a));
using namespace std;
typedef long long ll;
ll gcd(ll a, ll b) {return b ? gcd(b, a % b) : a;}
ll lcm(ll a, ll b) {return a / gcd(a, b) * b;}
ll powmod(ll a, ll b, ll MOD) { if (a == 0ll) {return 0ll;} a %= MOD; ll ans = 1; while (b) {if (b & 1) {ans = ans * a % MOD;} a = a * a % MOD; b >>= 1;} return ans;}
ll poww(ll a, ll b) { if (a == 0ll) {return 0ll;} ll ans = 1; while (b) {if (b & 1) {ans = ans * a ;} a = a * a ; b >>= 1;} return ans;}
void Pv(const vector<int> &V) {int Len = sz(V); for (int i = 0; i < Len; ++i) {printf("%d", V[i] ); if (i != Len - 1) {printf(" ");} else {printf("\n");}}}
void Pvl(const vector<ll> &V) {int Len = sz(V); for (int i = 0; i < Len; ++i) {printf("%lld", V[i] ); if (i != Len - 1) {printf(" ");} else {printf("\n");}}}
inline long long readll() {long long tmp = 0, fh = 1; char c = getchar(); while (c < '0' || c > '9') {if (c == '-') fh = -1; c = getchar();} while (c >= '0' && c <= '9') tmp = tmp * 10 + c - 48, c = getchar(); return tmp * fh;}
inline int readint() {int tmp = 0, fh = 1; char c = getchar(); while (c < '0' || c > '9') {if (c == '-') fh = -1; c = getchar();} while (c >= '0' && c <= '9') tmp = tmp * 10 + c - 48, c = getchar(); return tmp * fh;}
const int maxn = 300010;
const int inf = 0x3f3f3f3f;
/*** TEMPLATE CODE * * STARTS HERE ***/
int n;
pii a[maxn];
int b[maxn];
struct node
{
    int l, r, v;
} segment_tree[maxn << 2];
void pushup(int rt)
{
    segment_tree[rt].v = max(segment_tree[rt << 1].v, segment_tree[rt << 1 | 1].v);
}
void build(int rt, int l, int r)
{
    segment_tree[rt].l = l;
    segment_tree[rt].r = r;
    if (l == r)
    {
        segment_tree[rt].v = l;
        return ;
    }
    int mid = (l + r) >> 1;
    build(rt << 1, l, mid);
    build(rt << 1 | 1, mid + 1, r);
    pushup(rt);
}
void modify(int rt, int key, int val)
{
    if (segment_tree[rt].l == segment_tree[rt].r)
    {
        segment_tree[rt].v = val;
        return ;
    }
    int mid = (segment_tree[rt].l + segment_tree[rt].r) >> 1;
    if (key > mid)
    {
        modify(rt << 1 | 1, key, val);
    } else
    {
        modify(rt << 1, key, val);
    }
    pushup(rt);
}
int ask(int rt , int l, int r)
{
    if (segment_tree[rt].l >= l && segment_tree[rt].r <= r)
    {
        return segment_tree[rt].v;
    }
    int res = 0;
    int mid(segment_tree[rt].l + segment_tree[rt].r >> 1);
    if (l <= mid)
    {
        res = max(res, ask(rt << 1, l, r));
    }
    if (r > mid)
    {
        res = max(res, ask(rt << 1 | 1, l, r));
    }
    return res;
}
int R[maxn];
ll dp[maxn];
const ll mod = 998244353ll;
int main()
{
    //freopen("D:\\code\\text\\input.txt","r",stdin);
    //freopen("D:\\code\\text\\output.txt","w",stdout);
    n = readint();
    repd(i, 1, n)
    {
        a[i].fi = readint();
        a[i].se = readint();
    }
    sort(a + 1, a + 1 + n);
    repd(i, 1, n)
    {
        b[i] = a[i].fi;
    }
    build(1, 1, n);
    dp[n + 1] = 1ll;
    for (int i = n; i >= 1; --i)
    {
        int pos = upper_bound(b + 1, b + 1 + n, a[i].fi + a[i].se - 1) - b;
        R[i] = ask(1, i, pos - 1);
        modify(1, i, R[i]);
        dp[i] = dp[i + 1] + dp[R[i] + 1];
        dp[i] %= mod;
    }
    printf("%lld\n", dp[1] );
    return 0;
}




Measured memory_bytes: 14080