#include <bits/stdc++.h>
#define F first
#define S second
using namespace std;
const int maxn = 2 * 1e5 + 7;
const int LOG = 20;
const long long MOD = (long long)(1e9) + 7;
const long long base = 311;
const int ALP_BET = 26;
typedef pair<int, int> ii;
typedef pair<int, long long> il;
typedef pair<long long, int> li;
typedef pair<long long, long long> ll;
int add(int a, int b){
if(a + b < MOD)
return a + b;
return a + b - MOD;
}
int sub(int a, int b){
if(a - b >= 0)
return a - b;
return a - b + MOD;
}
int n;
int num[maxn], d[maxn];
namespace SUB1{
int f[maxn];
void solve(){
memset(f, 0, sizeof(f));
f[1] = 1;
for(int i = 1; i < n; ++i) if(d[i] != 0){
for(int k = 1; k <= num[i] && i + k * d[i] <= n; ++k){
f[i + k * d[i]] = add(f[i + k * d[i]], f[i]);
}
}
int ans = 0;
for(int i = 1; i <= n; ++i)
ans = add(ans, f[i]);
cout << ans << "\n";
return;
}
}
namespace FULL{
const int maxSQRT = 400 + 7;
const int LIM = 320;
int f[maxn];
int g[maxSQRT][maxSQRT];
vector<int> del[maxn];
void solve(){
memset(f, 0, sizeof(f));
memset(g, 0, sizeof(g));
for(int i = 1; i <= n; ++i)
del[i].clear();
f[1] = 1;
for(int i = 1; i <= n; ++i){
for(int dd = 1; dd <= LIM; ++dd){
f[i] = add(f[i], g[dd][i % dd]);
}
if(d[i] != 0 && num[i] != 0){
int dd = d[i];
if(dd > LIM){
for(int k = 1; k <= num[i] && i + k * dd <= n; ++k){
f[i + k * dd] = add(f[i + k * dd], f[i]);
}
} else{
g[dd][i % dd] = add(g[dd][i % dd], f[i]);
long long pos = 1LL * dd * num[i] + i;
if(pos <= n)
del[pos].push_back(i);
}
}
for(int id : del[i]){
int dd = d[id];
g[dd][id % dd] = sub(g[dd][id % dd], f[id]);
}
}
int ans = 0;
for(int i = 1; i <= n; ++i)
ans = add(ans, f[i]);
cout << ans << "\n";
return;
}
}
int main()
{
ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
// freopen("Trains.INP","r",stdin);
// freopen("Trains.OUT","w",stdout);
cin >> n;
for(int i = 1; i <= n; ++i)
cin >> d[i] >> num[i];
if(n <= 10000)
SUB1::solve();
else
FULL::solve();
return 0;
}
