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#include <iostream>
#include <vector>
#include <tuple>
#include <queue>
#include <numeric>

const long long MOD = 1'000'000'000 + 7;

struct segmentTree {
    int N = 1;
    std::vector<int> color;

    segmentTree(int n) {
        while(N < n) {
            N *= 2;
        }
        color.resize(2 * N, -1);
    }

    void insert(int l, int r, int v, int p, int q, int c) {
        if(q < l || r < p) {
            return;
        }
        if(p <= l && r <= q) {
            color[v] = c;
            return;
        }

        int m = (l + r) / 2;

        if(color[v] != -1) {
            color[2 * v] = color[v];
            color[2 * v + 1] = color[v];
        }

        insert(l, m, 2 * v, p, q, c);
        insert(m + 1, r, 2 * v + 1, p, q, c);

        if(color[2 * v] == color[2 * v + 1]) {
            color[v] = color[2 * v];
        } 
        else {
            color[v] = -1;
        }
    }

    void set(int p, int q, int c) {
        insert(0, N - 1, 1, p, q, c);
    }

    int get(int p) {
        p += N;
        int result = -1;
        while(p > 0) {
            if(color[p] != -1) {
                result = color[p];
            }
            p /= 2;
        }
        return result;
    }
};

long long mod_pow(long long a, long long b) {
    if(b == 0) {
        return 1;
    }
    if(b % 2 == 1) {
        return (a * mod_pow(a, b - 1)) % MOD;
    }
    long long x = mod_pow(a, b / 2);
    return (x * x) % MOD;
}

long long inverse(long long a) {
    return mod_pow(a, MOD - 2);
}

int main() {
    std::ios_base::sync_with_stdio(0);
    std::cin.tie(0);
    std::cin.tie(0);

    int N;
    std::cin >> N;

    std::vector<std::pair<int, int>> segments(N);
    for(auto& [p, q] : segments) {
        std::cin >> p >> q;
        q--;
    }

    std::vector<std::vector<int>> G(N);
    segmentTree tree(2*N);
    for(int i = 0; i < N; i++) {
        auto [p, q] = segments[i];
        int left = tree.get(p);
        int right = tree.get(q);

        if(left != -1) {
            G[i].push_back(left);
        }
        if(right != -1 && right != left) {
            G[i].push_back(right);
        }
        tree.set(p, q, i);
    }

    auto simple_prob = [&]() {
        std::vector<long long> cnt(N);

        for(int i = 0; i < N; i++) {
            std::queue<int> Q;
            std::vector<bool> visited(N);
            Q.push(i);
            visited[i] = true;

            while(!Q.empty()) {
                int v = Q.front();
                Q.pop();
                for(int u : G[v]) {
                    if(!visited[u]) {
                        visited[u] = true;
                        Q.push(u);
                        cnt[u]++;
                    }
                }
            }
        }

        return cnt;
    };
    auto cnt = simple_prob();

    long long A = 0, B = 1;
    for(int i = 0; i < N; i++) {
        long long C = 1, D = cnt[i] + 1;
        long long numerator = (A * D + B * C) % MOD;
        long long denominator = (B * D) % MOD;

        A = numerator;
        B = denominator;

        long long d = std::gcd(A, B);
        A /= d;
        B /= d;
    }

    std::cout << (A * inverse(B)) % MOD << '\n';

    return 0;
}