#include <stdio.h>
FILE *f =fopen("energii.in","r");
FILE *g=fopen("energii.out","w");
struct date
{
int eng ;
int cost;
} a[10000];
int G,W;
int cmin;
int main(void)
{
int i,j,ct,een;
int cost[10000]   ;
cmin=10000;
fscanf(f,"%d\n",&G);
fscanf(f,"%d\n",&W);
for  (i=1;i<=G;i++)
{
fscanf(f,"%d %d \n ",&a[i].eng,&a[i].cost);
cost[i]=a[i].cost;
if (a[i].eng>=W)
if (cmin>a[i].cost)
cmin=a[i].cost;
}
een=0;
ct=0;
for (i=1;i<=G-1;i++)
{
een=a[i].eng;
ct=a[i].cost;
for (j=i+1;j<=G;j++)
{
if (een<W)
{
een+=a[j].eng;
ct+=a[j].cost;
}
if (een>=W)
{
if (cmin>ct)
{
cmin=ct;
een=0;
ct=0;
}
een=0;
ct=0;
}
}
}
fprintf(g,"%d",cmin)   ;
fclose(g);
return(0);
}