typedef long long ll;
typedef long double ld;
#include <bits/stdc++.h>
using namespace std;
#define int long long

signed main(){
    ll n,V,c;
    std::cin >> n>>V>>c;
    vector<ll> v(2*n),w(2*n);
    for (int i = 0; i < n; i++) {
        std::cin >> v[2*i]>>w[2*i];
        v[2*i+1] = v[2*i];
        w[2*i+1] = w[2*i];
        w[2*i] += c;
    }
    
    vector<vector<ll>> dp(2*n+1,vector<ll>(V+1,-1e18));
    dp[0][0]=0;
    for (int i = 0; i < 2*n; i++) {
        for (int j = 0; j <= V; j++) {
            dp[i+1][j] = dp[i][j];
            if(i%2==0){
                if(j-v[i]>=0)dp[i+1][j] = max(dp[i+1][j],dp[i][j-v[i]]+w[i]);
            }else{
                if(j-v[i]>=0)dp[i+1][j] = max(dp[i+1][j],dp[i+1][j-v[i]]+w[i]);
            }
        }
    }
    ll ans = 0;
    for (int i = 0; i <= V; i++) {
        ans = max(ans, dp[2*n][i]);
    }
    std::cout << ans << std::endl;
}