#include <fstream>
using namespace std;

struct plasa{long long timp,peste;} v[1<<16];
int n,k,t;

ifstream in("peste.in");
ofstream out("peste.out");

bool cmp(plasa a,plasa b)
{
	return a.peste>b.peste;
}

int main()
{
	long long m=-1,r;
	int i,j,q;
	in>>n>>k>>t;
	for (i=1;i<=n;i++)
		in>>v[i].peste>>v[i].timp;
	sort(v+1,v+n+1,cmp);
	for (i=1;i<=1000;m=max(m,r*(t/i)),i++)
		for (j=q=1,r=0;j<=n && q<=k;j++)
			if (v[j].timp<=i)
			{
				r+=v[j].peste;
				q++;
			}
	out<<m<<"\n";
	return 0;
}