#include <iostream>
using namespace std;
const int maxn = 2005;
const int max_weight = 3550;
const int INF = 1e9;
int price[maxn], weights[maxn];
int n, W;
int dp[maxn][max_weight];
int rec(int at, int weight_left) {
    if(weight_left == 0) {
        return 0;
    }
    if(at == -1) {
        return 0;
    }
    if(dp[at][weight_left] != -1) {
        return dp[at][weight_left];
    }
    int result = -INF;
    result = max(result, rec(at - 1, weight_left));

    if(weight_left - weights[at] >= 0) {
        result = max(result, rec(at - 1, weight_left - weights[at]) + price[at]);
    }
    return dp[at][weight_left] = result;
}
int main() {
    cin >> n;
    for(int i = 0; i < n; i++) {
        cin >> price[i] >> weights[i];
    }
    cin >> W;
    for(int i = 0; i < maxn; i++) {
        for(int j = 0; j < max_weight; j++) {
            dp[i][j] = -1;
        }
    }
    cout << rec(n - 1, W) << endl;


    return 0;
}