#include<bits/stdc++.h>
typedef long long ll;
typedef unsigned long long ull;
using namespace std;
#define pb push_back
int dy[]={0, 0, 1, -1, 1, 1, -1, -1};
int dx[]={1, -1, 0, 0, 1, -1, -1, 1};

#define FOR(i,a,b) for (int i=(a);i<(b);i++)
#define RFOR(i,a,b) for (int i=(b)-1;i>=(a);i--)
#define REP(i,n) for (int i=0;i<(n);i++)
#define RREP(i,n) for (int i=(n)-1;i>=0;i--)
#define mp make_pair
#define fi first
#define sc second
#define INF (1e9)
int W,N,K;
int A[100],B[100];

int dp[51][10001][51];

int main(){
	cin >> W >> N >> K;
	REP(i,N) {
		cin >> A[i] >> B[i];
	}

	REP(i,W + 1) {
		REP(j,K + 1) {
			dp[0][i][j] = 0;
		}
	}

	FOR(i,1,N + 1) {
		REP(j,W + 1) {
			REP(k,K + 1) {
				if(0 <= j - A[i - 1] && 0 <= k - 1)
					dp[i][j][k] = max(dp[i - 1][j][k],dp[i - 1][j - A[i - 1]][k - 1] + B[i - 1]);
				else
					dp[i][j][k] = dp[i - 1][j][k];
			}
		}
	}

	cout << dp[N][W][K] << endl;
	return 0;
}