#include <bits/stdc++.h>
using namespace std;
#define MAXN 1000005
typedef int (*Comp)(int, int);
typedef long long lint;
const lint MOD = 1e9 + 7;
int N;
int A[MAXN], B[MAXN];
int mnseg[4 * MAXN], mxseg[4 * MAXN];
int chk[MAXN];
int cnt = -100;
int mn(int a, int b) { return (b == -1 || (a != -1 && A[a] < A[b])) ? a : b; }
int mx(int a, int b) { return (b == -1 || (a != -1 && B[a] > B[b])) ? a : b; }
void updseg(int seg[], int idx, int l, int r, int x, int y, Comp cmp) {
//if(idx == 1 && ++cnt < 100) printf("updseg(idx = %d, l = %d, r = %d, x = %d, y = %d)\n", idx, l, r, x, y);
if(l == r) seg[idx] = y;
else {
int m = (l + r) / 2;
if(x <= m) updseg(seg, idx * 2, l, m, x, y, cmp);
else updseg(seg, idx * 2 + 1, m + 1, r, x, y, cmp);
seg[idx] = cmp(seg[idx * 2], seg[idx * 2 + 1]);
}
//if(cnt < 100 && cmp(0, 1) == 0) printf("seg[24]**= %d\n", seg[24]);
}
int gseg(int seg[], int idx, int l, int r, int x, int y, Comp cmp) {
//if(++cnt < 100 && idx == 1) printf("gseg(l = %d, r = %d, x = %d, y = %d, %d)\n", l, r, x, y, cmp(0, 1));
//if(cnt < 100) printf("seg[%d] = %d\n", idx, seg[idx]);
if(x <= l && r <= y) return seg[idx];
if(r < x || y < l) return -1;
int m = (l + r) / 2;
//if(cnt < 100 && cmp(0, 1) == 0) printf("seg[24]*= %d\n", seg[24]);
return cmp(gseg(seg, idx * 2, l, m, x, y, cmp), gseg(seg, idx * 2 + 1, m + 1, r, x, y, cmp));
}
int findnode(int x) {
//if(++cnt < 100) printf("findnode(%d)\n", x);
int t = gseg(mnseg, 1, 1, 2 * N, A[x] + 1, B[x] - 1, mn);
//if(++cnt < 100) printf("t = %d\n", t);
if(t != -1 && A[t] < A[x]) return t;
t = gseg(mxseg, 1, 1, 2 * N, A[x] + 1, B[x] - 1, mx);
//if(++cnt < 100) printf("t = %d\n", t);
return (t == -1 || B[t] < B[x]) ? -1 : t;
}
void dfs(int x) {
//if(++cnt < 100) printf("dfs(%d)\n", x);
updseg(mnseg, 1, 1, 2 * N, B[x], -1, mn);
updseg(mxseg, 1, 1, 2 * N, A[x], -1, mx);
for(int t = findnode(x); t != -1; t = findnode(x)) {
chk[t] = 3 - chk[x];
dfs(t);
}
//if(++cnt < 100) printf("end dfs(%d)\n", x);
}
int main() {
lint ans = 1ll;
scanf("%d", &N);
for(int i = 0; i < N; i++) scanf("%d%d", A + i, B + i);
for(int i = 1; i < 8 * N; i++) mnseg[i] = mxseg[i] = -1;
for(int i = 0; i < N; i++) {
updseg(mnseg, 1, 1, 2 * N, B[i], i, mn);
updseg(mxseg, 1, 1, 2 * N, A[i], i, mx);
}
for(int i = 0; i < N; i++) if(!chk[i]) {
//printf("i = %d\n", i);
chk[i] = 1;
dfs(i);
ans = ans * 2 % MOD;
}
int cnt = 0;
for(int i = 0; i < N; i++) if(chk[i] == 1) {
chk[i] = 0;
updseg(mnseg, 1, 1, 2 * N, B[i], i, mn);
updseg(mxseg, 1, 1, 2 * N, A[i], i, mx);
}
for(int i = 0; i < N; i++) if(!chk[i]) {
cnt++;
chk[i] = 1;
dfs(i);
}
for(int i = 0; i < N; i++) if(chk[i] == 2) {
chk[i] = 0;
updseg(mnseg, 1, 1, 2 * N, B[i], i, mn);
updseg(mxseg, 1, 1, 2 * N, A[i], i, mx);
}
for(int i = 0; i < N; i++) if(!chk[i]) {
cnt++;
chk[i] = 2;
dfs(i);
}
if(cnt < N) printf("0");
else printf("%lld", ans);
return 0;
}
