/*
Pura gente del Coach Moy
*/
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pi = pair<int, int>;
using pll = pair<ll, ll>;
using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;
using vvll = vector<vll>;
#define fi first
#define se second
#define pb push_back
#define eb emplace_back
#define SZ(x) ((int)(x).size())
#define ALL(x) begin(x), end(x)
#define RALL(x) rbegin(x), rend(x)
#define FOR(i, a, b) for (int i = (int)a; i < (int)b; ++i)
#define ROF(i, a, b) for (int i = (int)a - 1; i >= (int)b; --i)
#define INF 1e18
#define ENDL '\n'
const int dx[] = {-1, 0, 1, 0};
const int dy[] = {0, 1, 0, -1};
const ll MOD = 1000000007;
inline int add(int x, int y, int m) {
return x + y < m ? x + y : x + y - m;
}
inline int sub(int x, int y, int m) {
return x >= y ? x - y : x - y + m;
}
inline int mul(int x, int y, int m) {
return int((ll)x * y % m);
}
int modPow(int x, int n, int m){
if(n == 0)
return 1;
int u = modPow(x, n / 2, m) % m;
u = mul(u, u, m);
if(n & 1)
u = mul(u, x, m);
return u;
}
signed main() {
cin.tie(0)->sync_with_stdio(0);
int n; cin >> n;
vector<pi> a(n); FOR(i, 0, n) cin >> a[i].first >> a[i].second;
map<int, int> mp;
FOR(i, 0, n){
if(mp.find(a[i].first) == mp.end()) mp[a[i].first] = SZ(mp);
if(mp.find(a[i].second) == mp.end()) mp[a[i].second] = SZ(mp);
}
map<int, int> rmp;
FOR(i, 0, n){
rmp[mp[a[i].first]] = a[i].first; a[i].first = mp[a[i].first];
rmp[mp[a[i].second]] = a[i].second; a[i].second = mp[a[i].second];
}
vi dp(SZ(mp));
ROF(i, n, 0){
int l = a[i].first, r = a[i].second;
int x = rmp[l];
FOR(j, l, r + 1){
int y = rmp[j + 1];
dp[i] = add(dp[i], mul(y - x + 1, dp[j], MOD), MOD);
}
int y = rmp[r];
dp[i] = add(dp[i], y - x + 1, MOD);
}
cout << dp[0] - 1;
return 0;
}
