ll n,x,y,z,a[500],b[500],d[6d4];{rd(n,x,a(n),b(n));REP(i,n){y=x-a[i];if(y>0)rrep(j,5d4)d[j]+=b[i],d[j]<?=d[j<y?j:j-y];else z-=y,n=0;d[1..5d4]<?=d[0..];}wt(n?-1:d[z]);}