#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
#define fi first
#define se second
#define vi vector<int>
#define vll vector<long long>
#define pii pair<int, int>
#define pll pair<long long, long long>
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng64(chrono::steady_clock::now().time_since_epoch().count());
inline int rand(int l,int r){return uniform_int_distribution<int>(l, r)(rng);}
inline ll rand(ll l,ll r){return uniform_int_distribution<ll>(l, r)(rng64);}
#ifdef DEBUG
auto&operator<<(auto&o,pair<auto,auto>p){return o<<"("<<p.first<<", "<<p.second<<")";}
auto operator<<(auto&o,auto x)->decltype(x.end(),o){o<<"{";int i=0;for(auto e:x)o<<","+!i++<<e;return o<<"}";}
#define debug(X...)cerr<<"["#X"]: ",[](auto...$){((cerr<<$<<"; "),...)<<endl;}(X)
#else
#define debug(...){}
#endif
struct custom_hash {
static uint64_t splitmix64(uint64_t x) {
x += 0x9e3779b97f4a7c15;
x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
return x ^ (x >> 31);
}
size_t operator()(uint64_t x) const {
static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
return splitmix64(x + FIXED_RANDOM);
}
};
struct Info{
ll ind, blokSz, blokMod, val;
Info(ll nind, ll nb, ll nm, ll nv){
ind = nind;
blokSz = nb;
blokMod = nm;
val = nv;
}
};
const int MAXN = 1e5 + 7;
const int B = 300;
ll d[MAXN];
ll x[MAXN];
ll dp[MAXN];
int n;
ll dod[B + 7][B + 7];
const int MOD = 1e9 + 7;
vector<Info> usu[MAXN];
int main(){
ios_base::sync_with_stdio(0);
cin.tie(NULL);
cout.tie(NULL);
cin >> n;
for(int i = 1; i <= n; i++){
cin >> d[i] >> x[i];
}
dp[1] = 1LL;
for(int i = 1; i <= n; i++){
for(auto ele : usu[i]){
dod[ele.blokSz][ele.blokMod] -= ele.val;
dod[ele.blokSz][ele.blokMod] += MOD;
dod[ele.blokSz][ele.blokMod] %= MOD;
}
for(int j = 1; j < B; j++){
dp[i] += dod[j][i % j];
dp[i] %= MOD;
}
if(dp[i] == 0LL || d[i] == 0){
continue;
}
if(d[i] >= B){
for(int j = 1; j <= x[i]; j++){
if(i + j * d[i] > n){
break;
}
dp[i + j * d[i]] += dp[i];
dp[i + j * d[i]] %= MOD;
}
continue;
}
dp[i] %= MOD;
dod[d[i]][i % d[i]] += dp[i];
dod[d[i]][i % d[i]] %= MOD;
if((ll)i + (ll)d[i] * x[i] + 1 <= n){
usu[(ll)i + (ll)d[i] * x[i] + 1].pb(Info(i + d[i] * x[i] + 1, d[i], i % d[i], dp[i]));
}
}
ll ans = 0LL;
for(int i = 1; i <= n; i++){
//cout << dp[i] << ' ';
ans += dp[i];
ans %= MOD;
}
//cout << '\n';
cout << ans << '\n';
return 0;
}
