// 01背包问题 一维优化
#include <iostream>
#include <algorithm>
using namespace std;

const int N = 1010;
int v[N], w[N], f[N];

int main() {
    int n, m;
    cin >> n >> m;

    for (int i = 1; i <= n; i++) cin >> v[i] >> w[i];

    for (int i = 1; i <= n; i++) {
        for (int j = m; j >= v[i]; j--) {
            f[j] = max(f[j], f[j - v[i]] + w[i]);
            // 朴素：f[i][j] = max(f[i - 1][j], f[i - 1][j - v[i]] + w[i])
        }
    }

    cout << f[m] << endl;

}

// 完全背包问题 最终版
#include <iostream>
#include <algorithm>
using namespace std;

const int N = 1010;
int v[N], w[N], f[N];

int main() {
    int n, m;
    cin >> n >> m;

    for (int i = 1; i <= n; i++) cin >> v[i] >> w[i];

    for (int i = 1; i <= n; i++) {
        for (int j = v[i]; j <= m; j++) {
            f[j] = max(f[j], f[j - v[i]] + w[i]);
            // 朴素：f[i][j] = max(f[i - 1][j], f[i][j - v[i]] + w[i])
        }
    }

    cout << f[m] << endl;

}

// 多重背包问题 朴素做法
#include <iostream>
#include <algorithm>
using namespace std;

const int N = 110;
int v[N], w[N], s[N];
int f[N][N];

int main() {
    int n, m;
    cin >> n >> m;

    for (int i = 1; i <= n; i++) {
        cin >> v[i] >> w[i] >> s[i]; 
    }

    // 三重循环
    for (int i = 1; i <= n; i++) {
        for (int j = 0; j <= m; j++) {
            for (int k = 0; k <= s[i] && k * v[i] <= j; k++) {
                f[i][j] = max(f[i][j], f[i - 1][j - k * v[i]] + k * w[i]);
            }
        }
    }

    cout << f[n][m] << endl;

    return 0;
}

// 多重背包问题II 利用二进制思想优化
#include <iostream>
#include <algorithm>
using namespace std;

const int N = 25000;
int v[N], w[N],f[N];

int main() {
    int n, m;
    cin >> n >> m;

    // 核心是划分s[i],然后对所有划分出来的数用01背包思想
    // 20: 1 2 4 8  5
    int cnt = 0;
    for (int i = 1; i <= n; i ++) {
        int a, b, s;
        cin >> a >> b >> s;

        int k = 1;
        while(k <= s) {
            cnt ++;
            v[cnt] = a * k;
            w[cnt] = b * k;
            s -= k;
            k *= 2;
        }
        if (s > 0) {
            cnt ++;
            v[cnt] = a * s;
            w[cnt] = b * s;
        }
    }
    n = cnt;

    // 01背包模板
    for (int i = 1; i <= n; i ++) {
        for (int j = m; j >= v[i]; j --) {
            f[j] = max(f[j], f[j - v[i]] + w[i]);
        }
    }

    cout << f[m] << endl;

    return 0;
}

// 分组背包问题
#include <iostream>
#include <algorithm>
using namespace std;

const int N = 110;
int v[N][N], w[N][N];
int f[N];
int s[N];
int n, m;

int main() {
    cin >> n >>m ;
    for (int i = 1; i <= n; i++) {
        cin >> s[i];
        for (int j = 1; j <= s[i]; j++) {
            cin >> v[i][j] >> w[i][j];
        }
    }

    // 01背包+每组选一种
    /* 
       j逆序是因为      f[j] = max(f[j],        f[j - v[i][k]]        + w[i][k])
       等价变形是    f[i][j] = max(f[i - 1][j], f[i - 1][j - v[i][k]] + w[i][k])
    */
    for (int i = 1; i <= n; i++) {
        for (int j = m; j >= 0; j--) {
            for (int k = 1; k <= s[i]; k++) {
                if (j >= v[i][k])
                    f[j] = max(f[j], f[j - v[i][k]] + w[i][k]);
            }
        }
    }

    cout << f[m] << endl;

    return 0;
}