#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

struct frac {
    long long int num, den;
    bool operator < (frac b) {
        return (1ll * num * b.den > 1ll * den * b.num);
    }
};

void reduce(frac &x) {
    long long int a = x.num, b = x.den;
    while (a != 0 and b != 0)
        if (a > b) a %= b; else b %= a;
    x.num /= (a + b); x.den /= (a + b);
}

int main()
{
    long long int n, w;
    cin >> n >> w;
    vector <frac> a(n);
    for (long long int i = 0; i < n; i++)
        cin >> a[i].num >> a[i].den;

    sort(a.begin(), a.end());
    long long int sum = a[0].den;

    long long int ind = 0;
    while (sum < w and ind < n) {
        ind++;
        sum += a[ind].den;
    }

    if (ind < n)
        sum -= a[ind].den;

    frac add;
    if (ind < n)
        add = {a[ind].num * (w - sum), a[ind].den};
    else
        add = {0,1};

    long long int int_part = 0;
    for (long long int i = 0; i < ind; i++)
        int_part += a[i].num;
    int_part += add.num / add.den;
    add.num = add.num % add.den;

    reduce(add);

    if (int_part == 0 && add.num == 0)
        cout << int_part;
    else if (int_part == 0)
        cout << add.num << "/" << add.den;
    else if (add.num == 0)
        cout << int_part;
    else
        cout << int_part << "+" << add.num << "/" << add.den;

}