#include <bits/stdc++.h>
//#define DEBUG 1106
#define int long long
#define ll long long
#define ld long double
#define pb emplace_back
#define p_q priority_queue
#define m_p make_pair
#define pii pair<int,int>
#define endl '\n'
#define INIT ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define FOR(i,a,b) for(int i = a; i <= b; i++)
#define forn(i,n) for (int i = 0; i < n; i++)
#define forn1(i,n) for (int i = 1; i <= n; i++)
#define all(x) x.begin(),x.end()
#define ft first
#define sd second
#define lowbit(x) (x&(-x))
#define chmax(x,y) x=max(x,y)
#define chmin(x,y) x=min(x,y)
#ifdef DEBUG
#define debug(x) cout << #x << ": " << x << endl;
#else
#define debug(x) 1106;
#endif
using namespace std;
const int N = 2e5+5;
const int inf = 1e9;
const int INF = 1e18;
const int MOD = 1e9+7;
int d[N], x[N];
int dp[N];
vector<pair<pii,int>> v[N];
int a[311][311];
signed main() {
INIT
#ifdef DEBUG
freopen("input.txt", "r", stdin);
#endif
///////////
int n;
cin >> n;
forn1(i,n) {
cin >> d[i] >> x[i];
}
int ans = 0;
dp[1] = 1;
forn1(i,n){
forn1(j,310) dp[i] = (dp[i]+a[j][i%j])%MOD;
if(d[i]<=310 && d[i]) {
a[d[i]][i%d[i]] += dp[i];
a[d[i]][i%d[i]] %= MOD;
if(i+(x[i]*d[i]) <= n) {
v[i+(x[i]*d[i])].pb(m_p(m_p(d[i],i%d[i]),dp[i]));
}
} else if(d[i]) {
for(int j = 1; i+(j*d[i])<=n && j<=x[i]; j++) {
dp[i+(j*d[i])]=(dp[i+(j*d[i])]+dp[i])%MOD;
}
}
for(auto j: v[i]) {
a[j.ft.ft][j.ft.sd] -= j.sd;
a[j.ft.ft][j.ft.sd] %= MOD;
if(a[j.ft.ft][j.ft.sd] < 0) {
a[j.ft.ft][j.ft.sd] = (a[j.ft.ft][j.ft.sd]+MOD+MOD) %MOD;
}
}
ans += dp[i];
ans %= MOD;
}
cout << ans;
}
