#pragma GCC target("avx2")
#pragma GCC optimize("unroll-loops")

#include <algorithm>
#include <bitset>
#include <climits>
#include <cmath>
#include <cstring>
#include <deque>
#include <forward_list>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

#define ALL(x) (x).begin(), (x).end()
#define PC(x) __builtin_popcount(x)
#define PCL(x) __builtin_popcountll(x)

using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
struct edge {
    int to, cost, id;
};
const double PI = 3.14159265358979323846;
const double PI2 = PI * 2.0;
const double EPS = 1E-09;
const ll MOD = 1E+09 + 7; // =998244353;
const ll INFL = 1E18;
const int INFI = 1E09;
const int MAX_N = 5000;

ll dx[4] = { 0, -1, 0, 1 }, dy[4] = { 1, 0, -1, 0 };

int N, V, C;

int VV[MAX_N + 1], W[MAX_N + 1], dp[MAX_N + 1][MAX_N + 1];

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    cin >> N >> V >> C;

    for (int i = 1; i <= N; ++i) {
        cin >> VV[i] >> W[i];
        // W[i] += C;
    }

    fill(dp[0], dp[N + 1], -INFI);
    for (int j = 0; j <= V; ++j) {
        dp[0][j] = 0;
    }
    for (int i = 1; i <= N; ++i) {
        vector<int> temp(V + 1, -INFI);
        for (int j = VV[i]; j <= V; ++j) {
            temp[j] = max(dp[i - 1][j - VV[i]] + W[i], temp[j - VV[i]] + W[i]);
        }
        for (int j = 0; j <= V; ++j) {
            dp[i][j] = max(dp[i - 1][j], temp[j] + C);
        }
    }

    // for (int i = 0; i < N; i++) {
    //     for (int j = 0; j < N; j++) {
    //         cout << "i = " << i << ", j = " << j << ", dp = " << dp[i][j] << "\n";
    //     }
    // }

    cout << dp[N][V] << "\n";

    return 0;
}