#include <fstream>
using namespace std;
  
int e[10000],c[10000],d[10000];
ifstream in("energii.in");
ofstream out("energii.out"); 
int main() {
    int n,i,j,sol,g,g2,k,l=0;
    in>>n>>g;
    for (i=1;i<=n;i++){
    in>>e[i]>>c[i];
    g2+=c[i];}
    for (i=1;i<=n;i++)
    for (j=g2-c[i];j>=0;j--)
        if (d[j+c[i]]<d[j]+e[i]) d[j+c[i]]=d[j]+e[i];
    while (l<=g2){
    	l++;
    	if (d[l]>=g) {out<<l;l=g2;}
    }
    if (d[g2]<g) out<<"-1";
}