/* Bismillahir Rahmanir Rahim */
#include <bits/stdc++.h>
using namespace std;
typedef pair<int, int> pii;
const int N = 2000005;
const int oo = 1e9;
void scanF(int &x){
register int c = getchar_unlocked();
x = 0;
for(;(c<48 || c>57);c = getchar_unlocked());
for(;c>47 && c<58;c = getchar_unlocked()) {x = (x<<1) + (x<<3) + c - 48;}
}
int n, st[N], en[N];
int lf[N], rf[N], idx[N];
int col[N], vis[N];
struct segtree{
int n;
pii mn[N*4], mx[N*4];
void build(int b, int e, int node){
if(b == e){
mn[node] = {lf[b], idx[b]};
mx[node] = {rf[b], idx[b]};
return;
}
int mid = (b + e) / 2, l = 2 * node, h = l + 1;
build(b, mid, l);
build(mid+1, e, h);
mn[node] = min(mn[l], mn[h]);
mx[node] = max(mx[l], mx[h]);
}
void update(int b, int e, int node, int pos){
if(b == e){
mx[node] = {-oo, -oo};
mn[node] = {+oo, +oo};
return;
}
int mid = (b + e) / 2, l = 2 * node, h = l + 1;
if(pos <= mid) update(b, mid, l, pos);
else update(mid+1, e, h, pos);
mn[node] = min(mn[l], mn[h]);
mx[node] = max(mx[l], mx[h]);
}
pii query_max(int b, int e, int node, int x, int y){
if(y < b || e < x) return {-oo, -oo};
if(b >= x && e <= y) return mx[node];
int mid = (b + e) / 2, l = 2 * node, h = l + 1;
return max(query_max(b, mid, l, x, y), query_max(mid+1, e, h, x, y));
}
pii query_min(int b, int e, int node, int x, int y){
if(y < b || e < x) return {+oo, +oo};
if(b >= x && e <= y) return mn[node];
int mid = (b + e) / 2, l = 2 * node, h = l + 1;
return min(query_min(b, mid, l, x, y), query_min(mid+1, e, h, x, y));
}
} tree;
void dfs(int at){
vis[at] = 1;
tree.update(1, n+n, 1, st[at]);
tree.update(1, n+n, 1, en[at]);
while(1){
pii f = tree.query_min(1, n+n, 1, st[at], en[at]);
if(f.first >= st[at]) break;
col[f.second] = col[at] ^ 1;
dfs(f.second);
}
while(1){
pii f = tree.query_max(1, n+n, 1, st[at], en[at]);
if(f.first <= en[at]) break;
col[f.second] = col[at] ^ 1;
dfs(f.second);
}
}
vector<int>g[N];
int flag;
int t[N*4];
void update(int b, int e, int node, int pos, int val){
if(b == e){
t[node] ^= (1 << val);
return;
}
int mid = (b + e) / 2, l = 2 * node, h = l + 1;
if(pos <= mid) update(b, mid, l, pos, val);
else update(mid+1, e, h, pos, val);
t[node] = t[l] | t[h];
}
int get(int b, int e, int node, int x, int y){
if(y < b ||e < x) return 0;
if(b >= x && e <= y) return t[node];
int mid = (b + e) / 2, l = 2 * node, h = l + 1;
return get(b, mid, l, x, y) | get(mid+1, e, h, x, y);
}
bool check(){
for(int i=1;i<=n+n;i++){
if(st[idx[i]] == i){
update(1, n+n, 1, st[idx[i]], col[idx[i]]);
}
else{
int g1 = get(1, n+n, 1, st[idx[i]]+1, en[idx[i]]);
int g2 = 1 << col[idx[i]];
if(g1 & g2) return false;
update(1, n+n, 1, st[idx[i]], col[idx[i]]);
}
}
return true;
}
int main(){
scanF(n);
for(int i=1;i<=n;i++){
scanF(st[i]);
scanF(en[i]);
lf[en[i]] = st[i];
lf[st[i]] = +oo;
rf[st[i]] = en[i];
rf[en[i]] = -oo;
idx[st[i]] = i;
idx[en[i]] = i;
}
tree.build(1, n+n, 1);
int comp = 0;
for(int i=1;i<=n;i++){
if(!vis[i]){
dfs(i);
++comp;
}
}
if(check() == false) printf("0\n");
else{
long long ret = 1LL;
long long mod = 1e9 + 7;
for(int i=1;i<=comp;i++){
ret *= 2LL;
ret %= mod;
}
printf("%lld\n", ret);
}
return 0;
}
