#include <bits/stdc++.h> using namespace std; #define int long long #define all(x) x.begin(), x.end() const int mod = 1e9 + 7; const int mxN = 1e5 + 10; const int mxS = 346; int dp[mxN], dp2[mxN][mxS + 5]; int add(int x, int y){ return ((x % mod) + (y % mod)) % mod; } int sub(int x, int y){ return ((((x + mod) % mod) - ((y + mod) % mod)) + mod) % mod; } void testCase() { int n; cin >> n; vector<pair<int, int>> v(n + 1); for(int i = 1; i <= n; ++i){ cin >> v[i].first >> v[i].second; } for(int i = 1; i <= n; ++i) dp[i] = 1; for(int i = n; i >= 1; --i){ if(v[i].first == 0) { for(int j = 1; j <= mxS; ++j){ if((i + j) <= n) dp2[i][j] = add(dp2[i + j][j], dp[i]); else dp2[i][j] = add(dp[i], mod); } } else{ if(v[i].first >= mxS){ for(int j = i + v[i].first, cnt = 1; j <= n && cnt <= v[i].second; j += v[i].first, cnt += 1){ dp[i] = add(dp[i], dp[j]); } }else{ if((i + v[i].first) <= n) { dp[i] = add(dp2[i + v[i].first][v[i].first], 1); if((i + (v[i].first * (v[i].second + 1))) <= n) dp[i] = sub(dp[i], dp2[i + (v[i].first * (v[i].second + 1))][v[i].first]); } } for(int j = 1; j <= mxS; ++j){ if((i + j) <= n) dp2[i][j] = add(dp2[i + j][j], dp[i]); else dp2[i][j] = add(dp[i], mod); } } } cout << add(dp[1], mod) << "\n"; } signed main(){ ios::sync_with_stdio(0); cin.tie(nullptr); cout.tie(nullptr); testCase(); return 0; }