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

#define int long long
#define double long double
#define pb push_back
#define mp make_pair
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define endl '\n'

int cnt(int n) {
    int ans = 0;
    while (n) {
        ++ans, n /= 10;
    }
    return ans;
}

signed main() {
    ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
    cout << fixed << setprecision(20);
#ifdef _DEBUG
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
    int n, k, t;
    cin >> n >> k >> t;
    vector<int> a(n);
    vector<int> pref(n + 1, 0);
    for (auto& i : a) {
        int x, y; char c;
        cin >> x >> c >> y;
        i = x * y;
    }
    sort(all(a)); for (int i = 0; i < n; ++i) pref[i + 1] = pref[i] + a[i];

    if (k > 1e11 || t > 1e11 || cnt(k) + cnt(t) >= 15) {
        cout << n; return 0;
    }
    const double eps = 1e-9;
    int ans = 0;
    for (int i = 0; i <= n; ++i) {
        if ((double)t - 1.0 * pref[i] / k > eps) {
            ans = max(ans, i);
        }
    }
    cout << ans;
}