#include <bits/stdc++.h>
using namespace std;
std::mt19937 rng(std::chrono::steady_clock::now().time_since_epoch().count());
#define int long long
const int sqr=350;
const int MX=1e5+7;
const int MOD=1e9+7;
int dp[sqr][MX+2*sqr];
int id[sqr][sqr];//onde eu to na mod i resto j
void solve() {
// vector<vector<vector<int>>> dp(sqr+1);//dp[i][j][k] mod i resto j prefixo k estado besta j
int n;cin>>n;
vector<int> resp(n,0);
vector<int> x(n);
vector<int> d(n);
for(int i=0;i<n;i++)cin>>d[i]>>x[i];
for(int i=1;i<sqr;i++){
for(int j=0;j<i;j++){
id[i][j]=i+j;
}
}
for(int i=n-1;i>=0;i--){
if(d[i]<sqr){
if(d[i]==0)resp[i]=1;
else{
resp[i]=1;
resp[i]+=((dp[d[i]][id[d[i]][i%d[i]]]-dp[d[i]][max((int)0,id[d[i]][i%d[i]]-(x[i]*d[i]))])%MOD+MOD)%MOD;
resp[i]%=MOD;
}
}
else{
int idat=i;
while(idat+d[i]<n && x[i]--){
idat+=d[i];
resp[i]+=resp[idat];
resp[i]%=MOD;
}
resp[i]++;
resp[i]%=MOD;
}
for(int j=1;j<sqr;j++){
id[j][i%j]+=j;
dp[j][id[j][i%j]]=(dp[j][id[j][i%j]-j]+resp[i])%MOD;
}
}
cout<<resp[0]%MOD;
return;
}
int32_t main() {
std::cin.tie(0)->sync_with_stdio(0);
std::cin.exceptions(std::cin.failbit);
int T = 1;
// std::cin >> T;
while(T--) {
solve();
}
return 0;
}
