#include <algorithm>
#include <queue>
using namespace std;

#define x first
#define y second

typedef long long ll;
const int MAX_N = 50005, MAX_T = 1005 ;


priority_queue < short > Q ;
pair < int, int > V[MAX_N] ;
int N,K,TT,H[MAX_T];
ll S[MAX_N],sol;

int main()
{
	int i,j;
	freopen("peste.in","r",stdin);
	freopen("peste.out","w",stdout);
	scanf ( "%d %d %d", &N, &K, &TT ) ;
	for ( int i = 0; i < N; ++i ) {
        scanf ( "%d %d", &V[i].y, &V[i].x ) ;
    }
	sort(V,V + N);
    for ( int i = 0, j = 1, k = 0; j <= 1000; ++j, H[j] = H[j - 1] )
	{
		for ( ; i < N && V[i].x == j ; Q.push ( -V[i].y ) , ++k, H[j] += V[i++].y ) ;
        for ( ; K < k ; H[j] += Q.top () , Q.pop (), --k ) ;
	}
	for ( int i = 0; i <= TT; ++i ) {
        if ( sol < S[i] ) {
            sol = S[i] ;
        }
        for ( int j = 1; j <= 1000; ++j ) {
            if ( S[i + j] < S[i] + H[j] ) {
                S[i + j] = S[i] + H[j] ;
            }
        }
    }
	printf ( "%lld", sol ) ;
}