#include <bits/stdc++.h>
using namespace std;
#define int long long
#ifdef LOCAL
void debug_out() {cerr<<endl;}
template <typename Head, typename... Tail>
void debug_out(Head _H, Tail... _T) {cerr<<" "<<to_string(_H);debug_out(_T...);}
#define debug(...) cerr<<"["<<#__VA_ARGS__<<"]:",debug_out(__VA_ARGS__)
#else
#define debug(...)
#endif
const int MAXN = 100005;
const int inf=1000000500ll;
const long long oo =1000000000000000500ll;
const int MOD = (int)1e9+7;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
typedef pair<int,int> pi;
const int sqn=400;
int n;
int D[MAXN], X[MAXN];
int dp[MAXN];
int R[1005][1005];
vector<array<int,3>> C[MAXN]; // at C_i, we need to remove x.first from x.second
int32_t main()
{
ios_base::sync_with_stdio(0); cin.tie(0);
cin >> n;
dp[1]=1;
for(int i=1;i<=n;i++){
cin>>D[i]>>X[i];
}
int ans=0;
for(int i=1;i<=n;i++){
for(int r=1;r<=sqn;r++){
dp[i]=(dp[i] + R[r][i%r])%MOD;
}
if(D[i] > sqn){
for(int t=1;t<=X[i];t++){
int idx=i+t*D[i];
if(idx<=n){
dp[idx] = (dp[idx] + dp[i])%MOD;
} else{
break;
}
}
} else{
if(D[i]){
R[D[i]][i%D[i]]=(R[D[i]][i%D[i]]+dp[i])%MOD;
int idx=min(n+1,i+X[i]*D[i]);
C[idx].push_back({D[i],i%D[i],dp[i]});
}
}
for(auto x:C[i]){
R[x[0]][x[1]]=(R[x[0]][x[1]]-x[2]+MOD)%MOD;
}
ans=(ans+dp[i])%MOD;
}
cout<<ans;
}
