#include<bits/stdc++.h>
#define god dimasi5eks
#pragma GCC optimize("O3")
#define fi first
#define se second
#define pb push_back
#define pf push_front
#define mod 1000000007
#define dancila 3.14159265359
#define eps 1e-9
// #define fisier 1
using namespace std;
typedef long long ll;
int n;
pair<int, int> bk[1000002];
bool oki[1000002];
int maxi[2000002];
int main()
{
#ifdef fisier
ifstream f("input.in");
ofstream g("output.out");
#endif
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> n;
for(int i = 1; i <= n; ++i)
cin >> bk[i].fi >> bk[i].se;
sort(bk + 1, bk + n + 1);
int maxx = 0;
int poz = 1;
for(int i = 1; i <= n+n; ++i)
{
if(bk[poz].fi == i)
maxx = bk[poz].fi, ++poz;
maxi[i] = maxx;
}
maxx = 0;
int cnt = 0;
int ans = 1;
for(int i = 1; i <= n; ++i)
{
if(maxx > bk[i].se)
{
oki[i] = 1;
if(maxi[bk[i].se] == bk[i].fi)
ans = (ans * 2) % mod;
}
else
maxx = bk[i].se, ++cnt;
}
set<int> x;
for(int i = 1; i <= n; ++i)
{
if(oki[i] == 1)
continue;
while(!x.empty() && *x.begin() < bk[i].fi)
x.erase(x.begin());
if(x.empty() && i != 1)
ans = (ans * 2) % mod;
x.insert(bk[i].se);
if(x.size() >= 3)
{
cout << 0;
return 0;
}
}
ans = (ans * 2) % mod;
cout << ans;
return 0;
}
