#include <fstream>
#include <vector>
#include <algorithm>
using namespace std;
ifstream fin("rucsac.in");
ofstream fout("rucsac.out");
int main(){
	int n,g;
	vector<pair<int,int>> a;
	fin>>n>>g;
	for(int i=0;i<n;i++){
		int w,p;
		fin>>w>>p;
		a.push_back({w,p});
	}
	sort(a.begin(),a.end(), [](auto &x,auto &y){
		return x.second > y.second;
		});
	int sumg=0,i=0,sum=0;
	while(sumg+a[i].first <= g){
		sum+=a[i].second;
		sumg+=a[i++].first;
	}
	fout<<sum<<'\n';
}