#include <cstdio>
#include <cstring>
#include <algorithm>
#include <vector>
#include <iostream>
#include <cassert>
#include <cmath>
#include <string>
#include <queue>
#include <set>
#include <map>
#include <cstdlib>
#include <unordered_set>
using namespace std;
#define INF 1e+9
#define mp make_pair
#define pb push_back
#define fi first
#define fs first
#define se second
#define i64 long long
#define li long long
#define lint long long
#define pii pair<int, int>
#define vi vector<int>
#define forn(i, n) for (int i = 0; i < (int)n; i++)
#define fore(i, b, e) for (int i = (int)b; i <= (int)e; i++)
#define MAX_FLAG 0
#define MIN_FLAG 1
const int MOD = 1e9+7;
const int maxn = 1e6+5;
const int inf = 1e9;
typedef int Tree[maxn * 8];
int s[maxn];
int f[maxn];
int inits[maxn];
int initf[maxn];
int n;
unordered_set<int> in_process;
Tree tree_max, tree_min;
int s_pos_to_i[2 * maxn];
int f_pos_to_i[2 * maxn];
int color[maxn];
int undef;
inline int select_max(int fi, int se) {
return f[fi] > f[se] ? fi : se;
}
inline int select_min(int fi, int se) {
return s[fi] < s[se] ? fi : se;
}
int get(const Tree& tree, int i, int L, int R, int A, int B, bool flag) {
//printf("get i = %d L = %d R = %d A = %d B = %d\n", i, L, R, A, B);
if (L >= B || A >= R)
return undef;
if (L >= A && R <= B)
return tree[i];
int M = (L + R) / 2;
int g1 = get(tree, 2 * i, L, M, A, B, flag);
int g2 = get(tree, 2 * i + 1, M, R, A, B, flag);
return flag == MAX_FLAG ? select_max(g1, g2) : select_min(g1, g2);
}
void upd(Tree& tree, int i, int L, int R, int pos, bool flag) {
if (L + 1 == R) {
tree[i] = undef;
return;
}
int M = (L + R) / 2;
if (pos < M)
upd(tree,i * 2, L, M, pos, flag);
else upd(tree, i * 2 + 1, M, R, pos, flag);
tree[i] = (flag == MIN_FLAG ? select_min(tree[i * 2], tree[i * 2 + 1]) : select_max(tree[i * 2], tree[i * 2 + 1]));
}
inline void add(int num) {
in_process.insert(num);
upd(tree_max, 1, 0, 2 * n, s[num], MAX_FLAG);
upd(tree_min, 1, 0, 2 * n, f[num], MIN_FLAG);
f[num] = -inf;
s[num] = inf;
}
void build(Tree& tree, int i, int L, int R, bool flag) {
// printf("build i = %d L = %d R = %d\n", i, L, R);
if (L + 1 == R) {
tree[i] = flag == MIN_FLAG ? f_pos_to_i[L] : s_pos_to_i[L];
return;
}
int M = (L + R) / 2;
build(tree, 2 * i, L, M, flag);
build(tree, 2 * i + 1, M, R, flag);
tree[i] = (flag == MIN_FLAG ? select_min(tree[i * 2], tree[i * 2 + 1]) : select_max(tree[i * 2], tree[i * 2 + 1]));
}
struct Event {
int num, x, typ;
};
bool operator < (Event first, Event second) {
return first.x < second.x;
}
int main() {
#ifdef LOCAL
freopen("inp", "r", stdin);
//freopen("outp", "w", stdout);
#else
// freopen(TASKNAME ".in", "r", stdin);
// freopen(TASKNAME ".out", "w", stdout);
#endif
scanf("%d", &n);
undef = n;
s[undef] = inf;
f[undef] = -inf;
forn(i, n) {
scanf("%d%d", &s[i], &f[i]);
--s[i];
--f[i];
inits[i] = s[i];
initf[i] = f[i];
//printf("s[%d] =%d f[%d] = %d\n", i, s[i], i, f[i]);
}
forn(i, 2 * n) {
f_pos_to_i[i] = s_pos_to_i[i] = undef;
}
forn(i, n) {
f_pos_to_i[f[i]] = i;
s_pos_to_i[s[i]] = i;
}
forn(i, n)
color[i] = 2;
build(tree_min, 1, 0, 2 * n, MIN_FLAG);
build(tree_max, 1, 0, 2 * n, MAX_FLAG);
int ans = 1;
/*forn(i, n) {
printf("s[%d] = %d f[%d] = %d\n", i, s[i], i, f[i]);
}*/
int start = 0;
while(true) {
while(start < n && color[start] != 2)
++start;
if (start == n)
break;
//printf("\n================\n");
//printf("start = %d\n", start);
ans = ans * 2 % MOD;
color[start] = 0;
add(start);
while(!in_process.empty()) {
int x = *in_process.begin();
//printf("x = %d [%d; %d]\n", x, inits[x], initf[x]);
in_process.erase(in_process.begin());
while(true) {
int next = get(tree_max, 1, 0, 2 * n, inits[x] + 1, initf[x], MAX_FLAG);
//printf("next = %d\n", next);
if (next == undef || f[next] < initf[x])
break;
color[next] = 1 - color[x];
add(next);
}
while(true) {
int next = get(tree_min, 1, 0, 2 * n, inits[x] + 1, initf[x], MIN_FLAG);
if (next == undef || s[next] > inits[x])
break;
color[next] = 1 - color[x];
add(next);
}
}
}
vector<Event> events;
forn(i, n) {
events.pb({i, inits[i], 1});
events.pb({i, initf[i], -1});
}
sort(events.begin(), events.end());
set<int> S[2];
/* forn(i, n)
printf("color[%d] = %d\n", i, color[i]);*/
for (const Event& event : events) {
//printf("event x = %d num = %d typ = %d\n", event.x, event.num, event.typ);
if (event.typ == 1) {
if (!S[color[event.num]].empty()) {
//printf("begin = %d\n", *S[1 - color[event.num]].begin());
if (*S[color[event.num]].begin() < initf[event.num]) {
printf("0");
exit(0);
}
}
S[color[event.num]].insert(initf[event.num]);
} else {
S[color[event.num]].erase(initf[event.num]);
}
}
printf("%d\n", ans);
}
