P153

//优化前
#include <iostream>

using namespace std;

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

int main (){
    cin >> n >> m;
    for (int i = 1 ; i <= n; i ++) cin >> v[i] >> w[i]; //i从1开始
    for (int i = 1; i <= n; i ++) //i从1开始，因为f[0][0~m]都是0，全局变量f[N][N]已经初始化过了
        for (int j = 0; j <= m; j ++) {
            f[i][j] = f[i - 1][j];
            if (j >= v[i])
                f[i][j] = max(f[i][j], f[i - 1][j - v[i]] + w[i]);
        }

    cout << f[n][m] << endl;
    return 0;
}

//优化后
#include <iostream>

using namespace std;

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

int main (){
    cin >> n >> m;
    for (int i = 1 ; i <= n; i ++) cin >> v[i] >> w[i]; //i从1开始
    for (int i = 1; i <= n; i ++) //i从1开始，因为f[0][0~m]都是0，全局变量f[N][N]已经初始化过了
        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;
}