#include <cstdio>
#include<vector>
#include<algorithm>
#include<utility>
#define nmax 1001
using namespace std;

vector<pair <int,int> > gen(nmax);
vector <long> D(5001+nmax);
int n,w,i;
long long cost_total;
void knapsack();

int main()
{
    FILE *f,*g;
    f=fopen("energii.in","r");
    g=fopen("energii.out","w");
    fscanf(f,"%d%d",&n,&w);
    for(i=1;i<=n;i++)
        fscanf(f,"%d%d",&gen[i].first,&gen[i].second),cost_total+=gen[i].second;
    if(cost_total<w)
        fprintf(g,"%lld",cost_total);
    else
        knapsack();
    fclose(f);
    fclose(g);
    return 0;
}
void knapsack()
{
    long long cw=1,max;
    while(1)
    {
        max=D[cw];
        for(i=1;i<=n;i++)
            if(gen[i]+D[cw-gen[i].first]>max)
                max=v[i]+D[cw-gen[i]].first;
        D[cw]=max;
        cw++;
        if(cw>=w &&D[cw])
            return D[cw];
    }
}