Language: C++

//#pragma GCC optimize("Ofast")
//#pragma GCC target("avx")
//#undef LOCAL




#include <algorithm>

#include <array>

#include <bitset>

#include <cassert>

#include <complex>

#include <cstdio>

#include <cstring>

#include <iostream>

#include <map>

#include <numeric>

#include <queue>

#include <set>

#include <string>

#include <unordered_map>

#include <unordered_set>

#include <vector>

using namespace std;

using uint = unsigned int;
using ll = long long;
using ull = unsigned long long;
constexpr ll TEN(int n) { return (n == 0) ? 1 : 10 * TEN(n - 1); }
template <class T> using V = vector<T>;
template <class T> using VV = V<V<T>>;

struct Scanner {
    FILE* fp = nullptr;
    char line[(1 << 15) + 1];
    size_t st = 0, ed = 0;
    void reread() {
        memmove(line, line + st, ed - st);
        ed -= st;
        st = 0;
        ed += fread(line + ed, 1, (1 << 15) - ed, fp);
        line[ed] = '\0';
    }
    bool succ() {
        while (true) {
            if (st == ed) {
                reread();
                if (st == ed) return false;
            }
            while (st != ed && isspace(line[st])) st++;
            if (st != ed) break;
        }
        if (ed - st <= 50) reread();
        return true;
    }
    template <class T, enable_if_t<is_same<T, string>::value, int> = 0>
    bool read_single(T& ref) {
        if (!succ()) return false;
        while (true) {
            size_t sz = 0;
            while (st + sz < ed && !isspace(line[st + sz])) sz++;
            ref.append(line + st, sz);
            st += sz;
            if (!sz || st != ed) break;
            reread();
        }
        return true;
    }
    template <class T, enable_if_t<is_integral<T>::value, int> = 0>
    bool read_single(T& ref) {
        if (!succ()) return false;
        bool neg = false;
        if (line[st] == '-') {
            neg = true;
            st++;
        }
        ref = T(0);
        while (isdigit(line[st])) {
            ref = 10 * ref + (line[st++] - '0');
        }
        if (neg) ref = -ref;
        return true;
    }
    template <class T> bool read_single(V<T>& ref) {
        for (auto& d : ref) {
            if (!read_single(d)) return false;
        }
        return true;
    }
    void read() {}
    template <class H, class... T> void read(H& h, T&... t) {
        bool f = read_single(h);
        assert(f);
        read(t...);
    }
    Scanner(FILE* _fp) : fp(_fp) {}
};

struct Printer {
  public:
    template <bool F = false> void write() {}
    template <bool F = false, class H, class... T>
    void write(const H& h, const T&... t) {
        if (F) write_single(' ');
        write_single(h);
        write<true>(t...);
    }
    template <class... T> void writeln(const T&... t) {
        write(t...);
        write_single('\n');
    }

    Printer(FILE* _fp) : fp(_fp) {}
    ~Printer() { flush(); }

  private:
    static constexpr size_t SIZE = 1 << 15;
    FILE* fp;
    char line[SIZE], small[50];
    size_t pos = 0;
    void flush() {
        fwrite(line, 1, pos, fp);
        pos = 0;
    }
    void write_single(const char& val) {
        if (pos == SIZE) flush();
        line[pos++] = val;
    }
    template <class T, enable_if_t<is_integral<T>::value, int> = 0>
    void write_single(T val) {
        if (pos > (1 << 15) - 50) flush();
        if (val == 0) {
            write_single('0');
            return;
        }
        if (val < 0) {
            write_single('-');
            val = -val; // todo min
        }
        size_t len = 0;
        while (val) {
            small[len++] = char('0' + (val % 10));
            val /= 10;
        }
        for (size_t i = 0; i < len; i++) {
            line[pos + i] = small[len - 1 - i];
        }
        pos += len;
    }
    void write_single(const string& s) {
        for (char c : s) write_single(c);
    }
    void write_single(const char* s) {
        size_t len = strlen(s);
        for (size_t i = 0; i < len; i++) write_single(s[i]);
    }
    template <class T> void write_single(const V<T>& val) {
        auto n = val.size();
        for (size_t i = 0; i < n; i++) {
            if (i) write_single(' ');
            write_single(val[i]);
        }
    }
};




template <class T> struct Fenwick {
    int n;
    V<T> seg;
    Fenwick(int _n = 0) : n(_n), seg(n) {}
    /// i番目の要素にxを追加する
    void add(int i, T x) {
        i++;
        while (i <= n) {
            seg[i - 1] += x;
            i += i & -i;
        }
    }
    /// [0, i)のsum
    T sum(int i) {
        assert(0 <= i && i <= n);
        T s = 0;
        while (i > 0) {
            s += seg[i - 1];
            i -= i & -i;
        }
        return s;
    }
    /// [a, b)のsum
    T sum(int a, int b) {
        assert(0 <= a && a <= b && b <= n);
        return sum(b) - sum(a);
    }
    /// sum[0, idx) >= xなる最小のidx(sum[0, n) < x なら n+1)
    int sum_lower_bound(T x) {
        if (x <= 0) return 0;
        int res = 0, len = 1;
        while (2 * len <= n) len *= 2;
        for (; len >= 1; len /= 2) {
            if (res + len <= n && seg[res + len - 1] < x) {
                res += len;
                x -= seg[res - 1];
            }
        }
        return res + 1;
    }
};


//binary gcd
ll gcd(ll _a, ll _b) {
    ull a = abs(_a), b = abs(_b);
    if (a == 0) return b;
    if (b == 0) return a;
    int shift = bsf(a|b);
    a >>= bsf(a);
    do {
        b >>= bsf(b);
        if (a > b) swap(a, b);
        b -= a;
    } while (b);
    return (a << shift);
}

/// g:gcd(a, b), ax+by=g
struct EG { ll g, x, y; };
EG ext_gcd(ll a, ll b) {
    if (b == 0) {
        if (a >= 0) return EG{a, 1, 0};
        else return EG{-a, -1, 0};
    } else {
        auto e = ext_gcd(b, a % b);
        return EG{e.g, e.y, e.x - a / b * e.y};
    }
}


ll inv_mod(ll x, ll md) {
    auto z = ext_gcd(x, md).x;
    return (z % md + md) % md;
}

template<class T, class U>
T pow_mod(T x, U n, T md) {
    T r = 1 % md;
    x %= md;
    while (n) {
        if (n & 1) r = (r * x) % md;
        x = (x * x) % md;
        n >>= 1;
    }
    return r;
}

// (rem, mod)
pair<ll, ll> crt(const V<ll>& b, const V<ll>& c) {
    int n = int(b.size());
    ll r = 0, m = 1;
    for (int i = 0; i < n; i++) {
        auto eg = ext_gcd(m, c[i]);
        ll g = eg.g, im = eg.x;
        if ((b[i] - r) % g) return {0, -1};
        ll tmp = (b[i] - r) / g * im % (c[i] / g);
        r += m * tmp;
        m *= c[i] / g;
    }
    return {(r % m + m) % m, m};
}

template <class I> struct Frac {
    I a, b; // a / b
    Frac(I _a = 0) : a(_a), b(1) {}
    Frac(I _a, I _b) {
        I g = gcd(_a, _b);
        if (_b < 0) g = -g;
        a = _a / g;
        b = _b / g;
    }
    Frac operator-() const {
        Frac f;
        f.a = -a;
        f.b = b;
        return f;
    }
    Frac operator+(const Frac& r) const { return {r.b * a + b * r.a, b * r.b}; }
    Frac operator-(const Frac& r) const { return *this + (-r); }
    Frac operator*(const Frac& r) const { return {a * r.a, b * r.b}; }
    Frac operator/(const Frac& r) const { return {a * r.b, b * r.a}; }
    Frac& operator+=(const Frac& r) { return *this = *this + r; }
    Frac& operator-=(const Frac& r) { return *this = *this - r; }
    Frac& operator*=(const Frac& r) { return *this = *this * r; }
    Frac& operator/=(const Frac& r) { return *this = *this / r; }
    bool operator<(const Frac& r) const { return a * r.b < b * r.a; }
    bool operator>(const Frac& r) const { return r < *this; }
    bool operator<=(const Frac& r) const { return !(r < *this); }
    bool operator>=(const Frac& r) const { return !(*this < r); }
    bool operator==(const Frac& r) const {
        return !(*this < r) && !(r < *this);
    }
    bool operator!=(const Frac& r) const { return !(*this == r); }

    static Frac rec(Frac x, Frac y, Frac l, Frac r) {
        auto flip = [&](Frac& f) { f = Frac(1) - f; };
        auto cross = [&](const Frac& f, const Frac& g) {
            return f.a * g.b - f.b * g.a;
        };
        Frac m = {l.a + r.a, l.b + r.b};
        if (x < m && m < y) return m;
        bool s = !(x < m);
        if (s) {
            flip(l);
            flip(r);
            flip(m);
            flip(x);
            flip(y);
            swap(l, r);
            swap(x, y);
        }
        I k = cross(r, y) / cross(y, l) + 1;
        Frac p = {k * l.a + r.a, k * l.b + r.b};
        if (x < p) {
            if (s) flip(p);
            return p;
        }
        Frac q = rec(x, y, p, {(k - 1) * l.a + r.a, (k - 1) * l.b + r.b});
        if (s) flip(q);
        return q;
    }
    static Frac in_bet(Frac x, Frac y) {
        if (y < x) swap(x, y);
        Frac ret;
        I num = x.a >= 0 ? x.a / x.b : -((x.b - 1 - x.a) / x.b);
        x.a -= x.b * num;
        y.a -= y.b * num;
        if (Frac{1, 1} < y)
            ret = Frac{1, 1};
        else
            ret = rec(x, y, Frac{0, 1}, Frac{1, 1});
        ret.a += ret.b * num;
        return ret;
    }
};

Scanner sc = Scanner(stdin);
Printer pr = Printer(stdout);


int main() {
    int n;
    sc.read(n);
    using P = pair<ll, ll>;
    V<P> v(n);
    for (int i = 0; i < n; i++) {
        sc.read(v[i].first, v[i].second);
    }
    sort(v.begin(), v.end(), [&](P a, P b) {
        return a.second > b.second;
    });

    V<int> idx(n);
    iota(idx.begin(), idx.end(), 0);
    sort(idx.begin(), idx.end(), [&](int a, int b) {
        return v[a].first < v[b].first;
    });
    V<int> ridx(n);
    for (int i = 0; i < n; i++) {
        ridx[idx[i]] = i;
    }

    Fenwick<int> fw0(n);
    Fenwick<ll> fw(n);
    for (int i = 0; i < n; i++) {
        fw0.add(i, 1);
        fw.add(i, v[idx[i]].first);
    }

          ;

    using F = Frac<__int128_t>;
    F ans = F(0, 1);

    ll sm = 0;
    for (int i = 0; i < n; i++) {
        P p = v[i];
        fw0.add(ridx[i], -1);
        fw.add(ridx[i], -p.first);

        int lw = fw.sum_lower_bound(sm - p.first);
        if (lw <= n) {
            ll rem = fw.sum(0, lw) + p.first - sm;
            int cnt = fw0.sum(0, lw);
                                   ;
            if (rem <= p.second) {
                F nx = F(cnt + 1, 1) - F(rem, p.second);
                                            ;
                ans = max(ans, nx);
            }
        }
        sm += max(0LL, p.second - p.first);
    }
    ans /= n;
    pr.writeln(ll(ans.a), ll(ans.b));
    return 0;
}


Compiler output:
a.cc: In function 'll gcd(ll, ll)':
a.cc:233:17: error: 'bsf' was not declared in this scope
  233 |     int shift = bsf(a|b);
      |                 ^~~