#include "bits/stdc++.h"
using namespace std;
#define ll long long
#define SZ(s) (int)s.size()
const int N = 5e2 + 5;
const int N1 = 1e6 + 5;
const int M = 1e9 + 7;
int a[N], b[N];
ll st[4 * N1];
vector <int> v;
int upd(int nd, int l, int r, int x, int vl) {
if(v[l] > x or v[r] < x) return st[nd];
if(v[l] == v[r]) {
st[nd] = (st[nd] + vl);
if(st[nd] >= M) st[nd] -= M;
return st[nd];
}
int md = (l + r) / 2;
st[nd] = (upd(nd*2, l, md, x, vl) + upd(nd*2+1, md+1, r, x, vl));
if(st[nd] >= M) st[nd] -= M;
return st[nd];
}
int fnd(int nd, int l, int r, int x) {
if(v[l] >= x) return 0;
if(v[r] < x) return st[nd];
int md = (l + r) / 2;
ll y = (fnd(nd*2, l, md, x) + fnd(nd*2+1, md+1, r, x));
if(y >= M) y -= M;
return y;
}
int main() {
ios_base::sync_with_stdio(false); cin.tie(nullptr);
int n;
cin >> n;
set <int> s;
s.insert(0);
for(int i = 1; i <= n; i++) {
cin >> a[i] >> b[i];
for(int j = a[i]; j <= b[i]; j++) {
s.insert(j);
}
}
int cnt = 0;
for(auto i : s) {
v.push_back(i);
}
upd(1, 0, SZ(v)-1, 0, 1);
ll ans = 0;
for(int i = 1; i <= n; i++) {
vector <int> v1;
for(int j = a[i]; j <= b[i]; j++) {
v1.push_back(fnd(1, 0, SZ(v)-1, j));
ans += v1.back();
if(ans >= M) ans -= M;
}
int cn = -1;
for(int j = a[i]; j <= b[i]; j++) {
upd(1, 0, SZ(v)-1, j, v1[++cn]);
}
}
cout << ans;
return 0;
}
