#include "bits/stdc++.h"
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair <ll,ll> pll;
typedef pair <int,int> pii;
typedef pair <int,pii> piii;
#define forr(_a,_b,_c) for(int _a = (_b); _a <= int (_c); ++_a)
#define ford(_a,_b,_c) for(int _a = (_b) + 1; _a --> int (_c);)
#define forf(_a,_b,_c) for(int _a = (_b); _a < int (_c); ++_a)
#define st first
#define nd second
#define pb push_back
#define mp make_pair
#define all(x) begin(x),end(x)
#define mask(i) (1LL << (i))
#define bit(x, i) (((x) >> (i)) & 1)
#define bp __builtin_popcountll
#define file "test"
template<class X, class Y>
bool minz(X &x, const Y &y) {
if (x > y) {
x = y;
return true;
} return false;
}
template<class X, class Y>
bool maxz(X &x, const Y &y) {
if (x < y) {
x = y;
return true;
} return false;
}
const int N = 2e5 + 5;
const ll oo = (ll) 1e16;
const ll mod = 1e9 + 7; // 998244353;
const int B = 317;
void add (ll &u, ll v){
u += v;
if (u >= mod)
u -= mod;
}
ll n, d[N], x[N];
namespace sub2 {
ll dp[N];
void solve(){
dp[1] = 1;
ll ans = 0;
forr (i, 1, n){
if (d[i]){
for (int j = 1; i + j * d[i] <= n && j <= x[i]; j++){
add(dp[i + j * d[i]], dp[i]);
}
}
add(ans, dp[i]);
}
cout << ans << "\n";
}
}
namespace sub4{
ll dp[N], f[B + 5][B + 5];
vector <int> dc[N];
void solve(){
dp[1] = 1;
ll ans = 0;
forr (i, 1, n){
forr (j, 1, B){
add(dp[i], f[j][i % j]);
}
if (d[i] && x[i]){
if (d[i] > B){
for (int j = 1; i + j * d[i] <= n && j <= x[i]; j++){
add(dp[i + j * d[i]], dp[i]);
}
} else {
add(f[d[i]][i % d[i]], dp[i]);
if (i + d[i] * x[i] <= n){
dc[i + d[i] * x[i]].pb(i);
}
}
}
for (int j : dc[i]){
add(f[d[j]][j % d[j]], mod - dp[j]);
}
add(ans, dp[i]);
}
cout << ans << "\n";
}
}
int main(){
ios_base::sync_with_stdio(0); cin.tie(0);
#ifdef kaguya
freopen(file".inp", "r", stdin); freopen(file".out", "w", stdout);
#endif
cin >> n;
forr (i, 1, n){
cin >> d[i] >> x[i];
}
if (n <= 4000){
sub2::solve();
} else {
sub4::solve();
}
return 0;
}
/*
*/
