#include <stdio.h>
 int N,E,a[20100];
 int ii,j,cost,castig,maxim;
int main()
{
    freopen("energii.in", "r", stdin);
    freopen("energii.out", "w", stdout);

    scanf("%d %d", &N, &E);
    for(ii=1;ii<=N;ii++)
    {
        scanf("%d %d", &castig, &cost);
        for(j=20001-cost;j>=0;j--)
        {
            if(a[j+cost]<a[j]+castig)
                a[j+cost]=a[j]+castig;
        }
    }

j=0;
while(a[j]<E)
 ++j;

if(j<=20000)
printf("%d", j);
else
printf("%d", -1);

    return 0;
}