#include "bits/stdc++.h"

using namespace std;

int mod = 1000007;
int main() {
    long long n,k;
    double t;
    cin >> n >> k >> t;

    long long arrSize[n];
    int a, b;
    char c;

    for(int i = 0; i < n; i++)
    {
        cin >> a >> c >> b;
        arrSize[i] = a*b;
    }

    sort(arrSize,arrSize+n);
    int index = 0;
    while(t>0 && index < n)
    {
        t-= (double)arrSize[index] / k;
        if(t>= 0) index++;
    }
    cout << index;
}