#include <bits/stdc++.h>
using namespace std;
using pii = pair<int, int>;
const int MOD = 1e9 + 7, INF = 1e9;
int N, A[1000009], B[1000009], C[1000009], P[2000009];
pii LA[1000009], RA[1000009];
struct segtree {
vector<pii> T;
void init(pii A[], int idx, int s, int e) {
if(s == e) {
T[idx] = A[s];
return;
}
int m = s+e >> 1;
init(A, idx*2, s, m);
init(A, idx*2+1, m+1, e);
T[idx] = max(T[idx*2], T[idx*2+1]);
}
void upd(int idx, int s, int e, int p, pii v) {
if(p < s || e < p) return;
if(s == e) {
T[idx] = v;
return;
}
int m = s+e >> 1;
upd(idx*2, s, m, p, v);
upd(idx*2+1, m+1, e, p, v);
T[idx] = max(T[idx*2], T[idx*2+1]);
}
pii get(int idx, int s, int e, int l, int r) {
if(r < s || e < l) return {-INF, -1};
if(l <= s && e <= r) return T[idx];
int m = s+e >> 1;
return max(get(idx*2, s, m, l, r), get(idx*2+1, m+1, e, l, r));
}
} LS, RS;
void dfs(int x, int c) {
C[x] = c;
RS.upd(1, 1, 2*N, A[x], {-INF, x});
LS.upd(1, 1, 2*N, B[x], {-INF, x});
while(1) {
int lm, rm, id; tie(rm, id) = RS.get(1, 1, 2*N, A[x] + 1, B[x] - 1);
if(rm > B[x]) {
dfs(id, 3 - c);
continue;
}
tie(lm, id) = LS.get(1, 1, 2*N, A[x] + 1, B[x] - 1); lm = -lm;
if(lm < A[x]) {
dfs(id, 3 - c);
continue;
}
break;
}
}
bool chk(vector<pii> S) {
sort(S.begin(), S.end());
vector<int> T;
for(auto& it: S) {
while(T.size() && T.back() < it.first) T.pop_back();
if(T.size() && T.back() < it.second) return false;
T.push_back(it.second);
}
return true;
}
int main() {
scanf("%d",&N);
LS.T.resize(8*N); RS.T.resize(8*N);
for(int i=1; i<=2*N; i++) LA[i] = RA[i] = {-INF, -1};
for(int i=1; i<=N; i++) {
scanf("%d%d",&A[i],&B[i]);
RA[A[i]] = {B[i], i};
LA[B[i]] = {-A[i], i};
}
LS.init(LA, 1, 1, 2*N); RS.init(RA, 1, 1, 2*N);
int ans = 1;
for(int i=1; i<=N; i++) if(!C[i]) {
dfs(i, 1);
ans *= 2; ans %= MOD;
}
vector<pii> AS, BS;
for(int i=1; i<=N; i++) {
if(C[i] == 1) AS.push_back({A[i], B[i]});
if(C[i] == 2) BS.push_back({A[i], B[i]});
}
if(!chk(AS) || !chk(BS)) return !printf("0");
printf("%d", ans);
return 0;
}
