https://www.lanqiao.cn/courses/31016/learning/?id=1898143&compatibility=false

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> PII;
typedef vector<long long> VI;
#define rep(i,a,n) for (int i=a;i<=n;i++)
#define per(i,a,n) for (int i=a;i>=n;i--)
#define pb(i) push_back(i)
#define int long long
#define INF 0x3f3f3f3f
#define oz  998244353
#define endl '\n'
#define N 200010
const int mod = 1e9 + 7;


int p[N], si[N];
int find(int x) {
    if (x == p[x])return p[x];
    p[x] = find(p[x]);
    return p[x];
}
//size[find(b)] += size[find(a)];
//p[find(a)] = find(b);


int n, k;
PII q[N];

int check(int x) {
    int num = 0;

    rep(i, 1, n) {
        auto [a, b] = q[i];
        num += (a / x) * (b / x);
    }

    return num >= k;
}
void solve() {
    cin >> n >> k;
    rep(i, 1, n) {
        int a, b;
        cin >> a >> b;
        q[i] = {a, b};
    }

    int l = 0, r = 1e18;

    while (l + 1 < r) {
        int mid = l + r >> 1;

        if (check(mid))l = mid;
        else r = mid;
    }

    if (check(l))cout << l <<  endl;
    else cout << r << endl;


}

signed main() {

    ios::sync_with_stdio(false);
    cin.tie(0), cout.tie(0);

    int T = 1;
//  cin >> T;
    while (T --)

        solve();

    return 0;
}