// Slower C++ solution:
#include <iostream>

#include <cstring>

using namespace std;

const int maxn=1e5+5;

long long dp[maxn];

long long w[maxn],v[maxn];

int main()

{

   int n,m;

   cin>>n>>m;

   memset(dp,0,sizeof(dp));

   for(int i=1;i<=n;++i){

       cin>>w[i]>>v[i];

   }

   for(int i=1;i<=n;++i){

       for(int j=m;j>=0;--j){

           if(j-w[i]>=0) dp[j]=max(dp[j],dp[j-w[i]]+v[i]);

       }

   }

   cout<<dp[m]<<endl;

   return 0;

}


// Faster C++ solution for the same problem (measured speedup: 1.8265484315059668x):
#include<bits/stdc++.h>

///...................................*****.................................................///

/// Author : Tanvir Ahmed ///

/// Department of Computer Science ///

/// & Engineering ///

/// Comilla University , Bangladesh. ///

///...................................*****.................................................///



/*....................................Values................................................*/

#define inf 1<<30

#define p5 100007

#define p6 1000007

#define PI acos(-1)

#define M 1000000007



/*....................................Functions.............................................*/

#define sqr(x) x*x

#define sc scanf

#define pf printf

#define scin(x) sc("%d",&(x))

#define scin2(x,y) sc("d",&(x),&(y))

#define scin3(x,y,z) sc("d%d",&(x),&(y),&(z))

#define scln(x) sc("%lld",&(x))

#define min3(a,b,c) min(a,min(b,c))

#define max3(a,b,c) max(a,max(b,c))

#define all(v) v.begin(), v.end()

#define ok cout << "ok" << endl

#define mem(x,y) memset(x,y,sizeof(x))

#define READ(f) freopen(f, "r", stdin)

#define WRITE(f) freopen(f, "w", stdout)



/*...................................Data_Types............................................*/

#define lli long long int

#define ull unsigned long long int

#define pii pair < int, int>

#define pll pair < ll, ll>

#define veci vector<int>

#define vecl vector<long long int>

#define vecp vector< pair<int,int> >

#define mapstrint map< string , int >

#define mapstrstr map< string , string >

#define mapint map< int, int >

#define uset unordered_set

#define umap unordered_map

#define pq priority_queue



#define pb push_back

#define mp make_pair

#define ss stringstream



/*.....................................Loops...............................................*/

#define rep( i , a , b ) for( i=a ; i<b ; i++)

#define rev( i , a , b ) for( i=a ; i>=b ; i--)

#define repx( i ,a,b, x) for( i=a ; i<b ; i+=x)



#define FastRead ios_base::sync_with_stdio(0);cin.tie(0)



//int month[]={31,28,31,30,31,30,31,31,30,31,30,31};

//long power(long int x, long int y){ int temp; if( y == 0) return 1; temp = power(x, y/2); if (y%2 == 0) return temp*temp; else return x*temp*temp; }

/*lli gcd(lli x,lli y)

{

if(x==0) return y;

return gcd(y%x,x);

}*/

/*

int dx[5] = {1, -1, 0, 0 };

int dy[5] = {0, 0, 1, -1};

*/



using namespace std;



lli n,W,profit[5][100005],w[105],val[105];



void knapsack(lli item,int chk)

{

    if(item>n)

        return;

    if(chk == 0)

    {

        for(int i=1; i<=W; i++)

        {

            if(i<w[item])

            {

                profit[1][i] = profit[0][i];

            }

            else if(profit[0][i]<(val[item]+profit[0][i-w[item]]))

                profit[1][i] = val[item]+profit[0][i-w[item]];

            else

                profit[1][i] = profit[0][i];

        }

        knapsack(item+1,1);

    }

    else

    {

        for(int i=1; i<=W; i++)

        {

            if(i<w[item])

            {

                profit[0][i] = profit[1][i];

            }

            else if(profit[1][i]<(val[item]+profit[1][i-w[item]]))

                profit[0][i] = val[item]+profit[1][i-w[item]];

            else

                profit[0][i] = profit[1][i];

        }

        knapsack(item+1,0);

    }

}



int main()

{

    scln(n);

    scln(W);

    for(int i=1; i<=n; i++)

    {

        scln(w[i]);

        scln(val[i]);

    }

    for(int i=0; i<=W; i++)

        profit[0][i] = 0;

    knapsack(1,0);

    if(n%2==1)

        pf("%lld\n",profit[1][W]);

    else

        pf("%lld\n",profit[0][W]);

    return 0;

}