#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 rau[1000002], maxi[2000002];
bool cmp(pair<int, int> a, pair<int, int> b)
{
if(a.se - a.fi == b.se - b.fi)
return a.fi < b.fi;
return a.se - a.fi < b.se - b.fi;
}
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, cmp);
int ans = 1;
set<int> x;
for(int i = 1; i <= n+n; ++i)
x.insert(i);
for(int i = 1; i <= n; ++i)
{
if(*x.upper_bound(bk[i].fi) == bk[i].se)
{
rau[bk[i].fi] = 1;
ans = (ans * 2) % mod;
x.erase(bk[i].fi);
x.erase(bk[i].se);
}
}
sort(bk + 1, bk + n + 1);
x.clear();
int cntmax = 0;
// cout << ans << '\n';
int beg = 0;
for(int i = 1; i <= n; ++i)
{
if(rau[bk[i].fi])
continue;
while(!x.empty() && *x.begin() < bk[i].fi)
{
cntmax -= maxi[*x.begin()];
x.erase(x.begin());
}
if(x.empty() && beg)
ans = (ans * 2) % mod;
if(x.empty() || *x.rbegin() < bk[i].se)
{
cntmax++;
maxi[bk[i].se] = 1;
}
if(!x.empty() && bk[i].se < *x.begin())
ans = (ans * 2) % mod;
x.insert(bk[i].se);
beg = 1;
if(cntmax >= 3)
{
cout << 0;
return 0;
}
// cout << i << " " << ans << '\n';
}
if(!x.empty())
ans = (ans * 2) % mod;
cout << ans;
return 0;
}
