import numpy as np
M=np.loadtxt(open(0),"q")
N,W=M[0];v,w=M[1:].T
V=W//(U:=w[i:=np.argmax(v/w)]*1000)*v[i]*1000;W%=U
dp=np.full(W+1,-10**9);dp[0]=0
R=np.arange(W+1)
for v,w in M[1:]:
	dp-=R//w*v
	for i in range(w):np.maximum.accumulate(dp[i::w],out=dp[i::w])
	dp+=R//w*v
print(V+dp.max())