#include<stdio.h>
using namespace std;
 
int i,j,n, eg[1001], cg[1001], v[5001]={0},cmin=-1;
 
int main() {
     
    freopen("energii.in", "r", stdin);
    freopen("energii.out", "w", stdout);
    int g, w;
    scanf("%d %d", &g, &w);
     
    for (i = 1; i <= g; i++) {
        scanf("%d %d", &eg[i], &cg[i]);
    }
     
     
    for( i = 1; i <= g; i++)
        for( j = w - eg[i]; j >= 0; j--) {
            if( v[j+eg[i]] < v[j] + cg[i] )
            {
                v[j+eg[i]] = v[j] + cg[i];
                if( v[j+eg[i]] > cmin)
                    cmin = v[j+eg[i]];
            }
        }
    printf("%d", cmin);
    return 0;
}