#include<bits/stdc++.h>
#define all(v) (v).begin(),(v).end()
#define pb push_back
#define ppb pop_back
#define mp make_pair
#define ri(x) scanf("%d",&(x))
#define ri2(x,y) scanf("%d %d",&(x),&(y))
#define ri3(x,y,z) scanf("%d %d %d",&(x),&(y),&(z))
#define rll(x) scanf("%lld",&(x))
#define rll2(x,y) scanf("%lld %lld",&(x),&(y))
#define rll3(x,y,z) scanf("%lld %lld %lld",&(x),&(y),&(z))
#define gc(x) ((x) = getchar())
using namespace::std;

const long double PI = acos(-1);
const long long MOD = 998244353;

typedef long long ll;
typedef pair<ll,ll> pll;
typedef pair<ll,pll> tll;
typedef pair<int,int> ii;
typedef pair<int,ii> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<iii> viii;
typedef vector<ll> vll;
typedef vector<pll> vpll;
typedef vector<tll> vtll;
typedef vector<string> vs;
typedef set<int> si;
typedef set<ii> sii;
typedef set<iii> siii;

ll gcd(ll a, ll b){ return b==0?a:gcd(b,a%b);}

ll add(ll a, ll b, ll m = MOD){
	if(a >= m) a %= m;
	if(b >= m) b %= m;
	if(a < 0) a += m;
	if(b < 0) b += m;
	ll res = a+b;
	if(res >= m or res <= -m) res %= m;
	if(res < 0) res += m;
	return res;
}

ll mul(ll a, ll b, ll m = MOD){
	if(a >= m) a %= m;
	if(b >= m) b %= m;
	if(a < 0) a += m;
	if(b < 0) b += m;
	ll res = a*b;
	if(res >= m or res <= -m) res %= m;
	if(res < 0) res += m;
	return res;
}

ll pow_mod(ll a, ll b, ll m = MOD){
	ll res = 1LL;
	a = a%m;
	while(b){
		if(b&1) res = mul(res,a,m);
		b >>= 1;
		a = mul(a,a,m);
	}
	return res;
}

ll fastexp(ll a, ll b){
	ll res = 1LL;
	while(b){
		if(b&1) res = res*a;
		b >>= 1;
		a *= a;
	}
	return res;
}

int gcdExtendido(int a, int b, int *x, int *y){
	if(a == 0){
		*x = 0;
		*y = 1;
		return b;
	}
	int x1, y1;
	int gcd = gcdExtendido(b%a,a,&x1,&y1);
	
	*x = y1-(b/a)*x1;
	*y = x1;
	return gcd;
}

int modInverso(int a, int m){
	int x, y;
	int g = gcdExtendido(a,m,&x,&y);
	if(g!=1) return -1;
	else return (x%m + m)%m;
}

/****************************************
*************P*L*A*N*T*I*L*L*A************
*****************************************/

const int N = 200000+5;

int n;
int x[N];
int d[N];
int nxt[N];
int st[4*N];
int memo[N];

void update(int x, int y, int pos = 1, int l = 0, int r = n){
	if(l == r){
		st[pos] = y;
		return;
	}
	int mi = (l+r)/2;
	if(l <= x and x <= mi) update(x,y,2*pos,l,mi);
	else update(x,y,2*pos+1,mi+1,r);
	st[pos] = max(st[2*pos],st[2*pos+1]);
}

int query(int x, int y, int pos = 1, int l = 0, int r = n){
	if(y < l or r < x or x > y) return 0;
	if(x <= l and r <= y) return st[pos];
	int mi = (l+r)/2;
	return max(query(x,y,2*pos,l,mi),query(x,y,2*pos+1,mi+1,r));
}

void modify(int &r, int pos){
	r = max(r, x[pos] + d[pos] - 1);
}

int main(){
	ri(n);
	vi p(n);
	for(int i=0; i<n; i++){
		ri2(x[i],d[i]);
		p[i] = i;
	}
	sort(all(p),[&](int i, int j){
		return x[i] < x[j];
	});
	x[n] = INT_MIN;
	p.emplace_back(n);
	memo[n] = 1;
	for(int i=n-1; i>=0; i--){
		int j;
		int R = x[p[i]] + d[p[i]] - 1;
		int lo = i, hi = n;
		while(lo < hi){
			int mi = lo + (hi - lo + 1) / 2;
			if(x[p[mi]] <= R) lo = mi;
			else hi = mi-1;
		}
		j = max(query(i,lo), i+1);
		memo[i] = add(memo[i+1], memo[j]);
		update(i, j);
	}
	printf("%d\n",memo[0]);
	return 0;
}


Measured memory_bytes: 7280