#include<stdio.h>
#include<stdlib.h>
int g,w,e[10001],c[10001];
int vector[50005001],vector2[50005001];
int main(){
	int i,j;
	FILE *fin=fopen("energii.in","r");
	fscanf(fin,"%d",&g);
	fscanf(fin,"%d",&w);
	for(i=1;i<=g;i++)
		fscanf(fin,"%d %d",&e[i],&c[i]);
	/*for(i=1;i<=g;i++)
		printf("%d %d \n",e[i],c[i]);
*/
	//printf("w=%d",w);
	FILE *fout=fopen("energii.out","w");
	
	long min=500000000;
	int puse=1,sarite=0;
	vector[1]=e[1];
	vector2[1]=c[1];
	for(j=2;(j<=g);j++){
		puse+=puse-sarite;
		if(c[j]<=min){
		vector[puse]=e[j];
		vector2[puse]=c[j];
		if((vector[puse]>=w)&&(min>vector2[puse]))
		min=vector2[puse];
		//printf("min=%d\n\n",min);
		sarite=0;
		for(i=1;i<puse;i++){
			if(vector2[i]+vector2[puse]<=min){
				vector[i+puse-sarite]=vector[puse]+vector[i];//printf("%d ",vector[i+puse-sarite]);
			vector2[i+puse-sarite]=vector2[puse]+vector2[i];//printf("%d\n",vector2[i+puse-sarite]);
			if(vector[i+puse-sarite]>=w&&vector2[puse]+vector2[i]<min)
				min=vector2[puse]+vector2[i];
			}
			else{
			sarite++;
		//	printf("sarite%d\n",min);
			}
		}
		}
		//else
		//	puse-=puse-sarite;
	}
	for(i=1;i<20;i++)
		printf("%d %d \n",vector[i],vector2[i]);
	if(min!=500000000)
	fprintf(fout,"%ld\n",min);
	else
		fprintf(fout,"-1\n");
	fprintf(fout,"\n");
	return 0;
}