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#include <bits/stdc++.h>
using namespace std;

#define SIZE 1024

#define pii pair<int, int>
#define ll long long
#define MOD 1000000007ll

int tree[2100000];

int read(int i) {
    int p = 0;
    while (i > 0) {
        if (tree[i] != 0) {
            p = tree[i];
        }
        i /= 2;
    }
    return p;
}

void insert(int p, int a, int b, int l, int r, int val) {
    if (a > r || b < l) {
        return;
    }
    if (a >= l && b <= r) {
        tree[p] = val;
        return;
    }

    if (tree[p] != 0) {
        tree[2 * p] = tree[p];
        tree[2 * p + 1] = tree[p];
        tree[p] = 0;        
    }


    insert(2 * p, a, (a + b) / 2, l, r, val);
    insert(2 * p + 1, (a + b) / 2 + 1, b, l, r, val);
}

int l[500007];
int r[500007];

void print_tree(int m) {
    int p = 1, i = 1;
    while (i < 2 * m) {
        for (int j = 0; j < p; j++) {
            cout << tree[i + j] << " ";
        }
        cout << "\n";
        i += p;
        p *= 2;
    }
}

ll power(ll base, ll ind) {
    ll out = 1ll;
    while (ind > 0ll) {
        if (ind % 2ll == 1ll) {
            out *= base;
            out %= MOD;
        }
        ind /= 2ll;
        base *= base;
        base %= MOD;
    }
    return out;
}

ll inv[500007];
int anc[500007];

void print_anc(int n) {
    for (int i = 1; i <= n; i++) {
        cout << i << ": " << anc[i] << "\n";
    }
}

void push_down(int v, int k, vector<bitset<SIZE>>& pred) {
    if ((v - 1) / SIZE == k) {
        pred[v] |= (bitset<SIZE>(1) << ((v - 1) % SIZE));
    }
    if (l[v] != 0) {
        pred[l[v]] |= pred[v];
    }
    if (r[v] != 0 && r[v] != l[v]) {
        pred[r[v]] |= pred[v];
    }
}


int main() {

    ios_base::sync_with_stdio(0);
    cin.tie(0);

    int n;
    cin >> n;

    for (int i = 1; i <= n; i++) {
        inv[i] = power((ll)(i), MOD - 2ll);
    }

    int m = 1;
    while (m < 2 * n) {
        m *= 2;
    }

    for (int i = 1; i <= n; i++) {
        int a, b;
        cin >> a >> b;

        l[i] = read(a + m - 1);
        r[i] = read(b + m - 1);

        if (a + 1 <= b - 1)
            insert(1, m, 2 * m - 1, a + m - 1 + 1, b + m - 1 - 1, i);
    }

    for (int k = 0; k < (n + SIZE - 1) / SIZE; k++) {
        vector<bitset<SIZE>> pred(n + 1, bitset<SIZE>(0ll));
        for (int i = n; i >= 1; i--) {
            push_down(i, k, pred);
            anc[i] += (int)(pred[i].count());
        }        
    }

    ll out = 0;
    for (int i = 1; i <= n; i++) {
        out += inv[anc[i]];
        out %= MOD;
    }

    cout << out << "\n";

}