#include<bits/stdc++.h>
#define endl '\n'
#define a first
#define b second
using namespace std;
typedef long long ll;
const int MAXN = 500 + 10;
const int MAXA = 1e6 + 10;
const int MOD = 1e9 + 7;
int n,cnt;
int a[MAXN];
int b[MAXN];
int dp[MAXA];
int pref[MAXA];
unordered_map <int,int> pos;
void read()
{
cin >> n;
for(int i = 1; i <= n; i++)
{
cin >> a[i] >> b[i];
}
a[0] = b[0] = -1;
}
void fill_pos()
{
set <int> st;
for(int i = 1; i <= n; i++)
{
int from = a[i];
int to = b[i];
for(int j = from; j <= to; j++)
{
st.insert(j);
}
}
int last = -1;
for(int cur : st)
{
if(cur == last)
continue;
pos[cur] = ++cnt;
last = cur;
}
/**
for(auto x : pos)
{
cout << x.first << " " << x.second << endl;
}
*/
}
void fill_dp()
{
for(int i = 1; i <= n; i++)
{
int from = pos[a[i]];
int to = pos[b[i]];
for(int j = to; j >= from; j--)
{
dp[j] = (dp[j] + pref[j - 1] + 1 /** za nulata **/) % MOD;
}
for(int j = from; j <= cnt; j++)
{
pref[j] = (pref[j - 1] + dp[j]) % MOD;
}
}
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
read();
fill_pos();
fill_dp();
cout << pref[cnt] << endl;
return 0;
}
