#include <iostream>

using namespace std;

int dp[2000][2100];

int main(){
  int n,i;cin>>n>>i;
  for(int i = 0; n > i; i++){
    int a,b;cin>>a>>b;
    for(int j = 0; 1000 >= j; j++){
      dp[i+1][j+a] = max(dp[i][j+a],dp[i][j]+b);
      dp[i+1][j] = max(dp[i+1][j],dp[i][j]);
    }
  }
  cout << dp[n][i] << endl;
}