#include <bits/stdc++.h>
const int32_t MAX_N = 1e6;
const int32_t INF = 2e9;
const int32_t MOD = 1e9 + 7;
class SegmentTree {
private:
bool isMax;
int32_t treeSize;
int32_t data[8 * MAX_N + 5];
void Update(int32_t node, int32_t low, int32_t high, int32_t qInd, int32_t qVal) {
if(low > qInd || high < qInd) {
return;
}
else if(low == qInd && high == qInd) {
data[node] = qVal;
return;
}
int32_t mid = (low + high) / 2;
Update(2 * node, low, mid, qInd, qVal);
Update(2 * node + 1, mid + 1, high, qInd, qVal);
if(isMax) {
data[node] = std::max(data[2 * node], data[2 * node + 1]);
}
else {
data[node] = std::min(data[2 * node], data[2 * node + 1]);
}
}
int32_t Query(int32_t node, int32_t low, int32_t high, int32_t qLow, int32_t qHigh) {
if(low > qHigh || high < qLow) {
if(isMax) {
return -1;
}
else {
return INF;
}
}
else if(low >= qLow && high <= qHigh) {
return data[node];
}
int32_t mid = (low + high) / 2;
if(isMax) {
return std::max(Query(2 * node, low, mid, qLow, qHigh), Query(2 * node + 1, mid + 1, high, qLow, qHigh));
}
else {
return std::min(Query(2 * node, low, mid, qLow, qHigh), Query(2 * node + 1, mid + 1, high, qLow, qHigh));
}
}
public:
void Init(int32_t _treeSize, bool _isMax) {
treeSize = _treeSize;
isMax = _isMax;
}
void Update(int32_t ind, int32_t val) {
Update(1, 1, treeSize, ind, val);
}
int32_t Query(int32_t low, int32_t high) {
return Query(1, 1, treeSize, low, high);
}
};
int32_t comps[MAX_N + 5], indOf[2 * MAX_N + 5];
std::pair< int32_t, int32_t > a[MAX_N + 5];
SegmentTree segTreeStarts, segTreeEnds;
void Dfs(int32_t ind, int32_t currComp) {
comps[ind] = currComp;
segTreeStarts.Update(a[ind].first, -1);
segTreeEnds.Update(a[ind].second, INF);
while(1) {
int32_t aux = segTreeStarts.Query(a[ind].first + 1, a[ind].second - 1);
if(aux > a[ind].second) {
Dfs(indOf[aux], (currComp ^ 1));
}
else {
break;
}
}
while(1) {
int32_t aux = segTreeEnds.Query(a[ind].first + 1, a[ind].second - 1);
if(aux < a[ind].first) {
Dfs(indOf[aux], (currComp ^ 1));
}
else {
break;
}
}
}
bool Check(int32_t n) {
std::vector< int32_t > side1, side2;
for(int32_t i = 0; i < n; i++) {
if(comps[i] == 0) {
side1.push_back(i);
}
else {
side2.push_back(i);
}
}
std::stack< int32_t > st;
for(auto &x : side1) {
while(!st.empty() && st.top() < a[x].first) {
st.pop();
}
if(!st.empty() && st.top() < a[x].second) {
return false;
}
else {
st.push(a[x].second);
}
}
while(!st.empty()) {
st.pop();
}
for(auto &x : side2) {
while(!st.empty() && st.top() < a[x].first) {
st.pop();
}
if(!st.empty() && st.top() < a[x].second) {
return false;
}
else {
st.push(a[x].second);
}
}
return true;
}
int main() {
std::ios_base::sync_with_stdio(false);
std::cin.tie(nullptr);
int32_t n;
std::cin >> n;
segTreeStarts.Init(2 * n, 1);
segTreeEnds.Init(2 * n, 0);
for(int32_t i = 0; i < n; i++) {
std::cin >> a[i].first >> a[i].second;
segTreeStarts.Update(a[i].first, a[i].second);
segTreeStarts.Update(a[i].second, -1);
segTreeEnds.Update(a[i].second, a[i].first);
segTreeEnds.Update(a[i].first, INF);
}
std::sort(a, a + n);
for(int32_t i = 0; i < n; i++) {
indOf[a[i].first] = i;
indOf[a[i].second] = i;
}
int32_t cntComps = 0;
memset(comps, -1, sizeof(comps));
for(int32_t i = 0; i < n; i++) {
if(comps[i] == -1) {
cntComps++;
Dfs(i, 0);
}
}
if(Check(n)) {
int32_t ans = 1;
for(int32_t i = 0; i < cntComps; i++) {
ans = ((int64_t) 2 * ans) % MOD;
}
std::cout << ans << '\n';
}
else {
std::cout << 0 << '\n';
}
}
