#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll MOD = 1'000'000'007;
int main() {
int n;
cin >> n;
vector<pair<int, int>> range(n);
set<int> all_values;
// Read input and collect all possible boat values
for (int i = 0; i < n; ++i) {
int a, b;
cin >> a >> b;
range[i] = {a, b};
all_values.insert(a);
all_values.insert(b);
}
// Optional: if ranges are small enough (like in subtasks), include full ranges
// Otherwise just store a and b and assume ranges will be reconstructed later
// Coordinate compression
vector<int> vals(all_values.begin(), all_values.end());
unordered_map<int, int> val_to_index;
int m = vals.size();
for (int i = 0; i < m; ++i) {
val_to_index[vals[i]] = i;
}
// dp[i]: number of ways to form a valid sequence ending in boat value vals[i]
vector<ll> dp(m, 0);
// For the first school
for (int i = 0; i < m; ++i) {
int x = vals[i];
if (x >= range[0].first && x <= range[0].second) {
dp[i] = 1;
}
}
for (int school = 1; school < n; ++school) {
// Build prefix sum over previous dp
vector<ll> prefix(m + 1, 0);
for (int i = 0; i < m; ++i) {
prefix[i + 1] = (prefix[i] + dp[i]) % MOD;
}
vector<ll> new_dp(m, 0);
for (int i = 0; i < m; ++i) {
int x = vals[i];
if (x >= range[school].first && x <= range[school].second) {
// Valid values are strictly greater than previous values
new_dp[i] = prefix[i]; // sum of all dp[j] where j < i
}
}
// Also allow school to skip sending boats — keep previous dp values
for (int i = 0; i < m; ++i) {
new_dp[i] = (new_dp[i] + dp[i]) % MOD;
}
dp = new_dp;
}
// Answer: sum over all dp[i], but must have used at least one boat
ll ans = 0;
for (ll x : dp) {
ans = (ans + x) % MOD;
}
cout << ans << '\n';
return 0;
}
