#include<bits/stdc++.h>
using namespace std;
#define ll long long
const ll inf=1e18;
const int maxn=20000005;
ll n,wc,v[25],w[25],dp[maxn];
int main(){
    ll ans,lm,id;
    int i,j;
    ans=0; lm=20000000; id=1;
    if(scanf("%lld%lld",&n,&wc)!=2) return 0;
    for(i=1;i<=n;i++) scanf("%lld%lld",&v[i],&w[i]);
    for(i=2;i<=n;i++) if(v[i]*w[id]>v[id]*w[i]) id=i;
    if(wc<lm) lm=wc;
    for(i=1;i<=lm;i++) dp[i]=-1;
    for(i=0;i<=lm;i++){
        if(dp[i]==-1) continue;
        for(j=1;j<=n;j++) if(i+w[j]<=lm) dp[i+w[j]]=max(dp[i+w[j]],dp[i]+v[j]);
    }
    for(i=0;i<=lm;i++){
        if(dp[i]==-1) continue;
        ans=max(ans,dp[i]+(wc-i)/w[id]*v[id]);
    }
    printf("%lld\n",ans);
    return 0;
}