#!/usr/bin/env PyPy3

from collections import Counter, defaultdict, deque
import itertools
import re
import math
from functools import reduce
import operator
import bisect
from heapq import *
import functools
mod=998244353

import sys
input=sys.stdin.readline
n,V,c=map(int,input().split())
INF = 1 << 31
dp = [[-INF] * (V+1) for _ in range(n+1)]
dp[0][0] = 0
for i in range(n):
    v,w=map(int,input().split())
    for j in range(1,i+2)[::-1]:
        for k in range(min(v,V+1)):
            tmp = dp[j-1][k]
            for x in range(k+v,V+1,v):
                tmp = max(tmp+w,dp[j-1][x-v]+w)
                dp[j][x] = max(tmp,dp[j][x])
ans = 0
for i in range(n+1):
    for j in range(V+1):
        ans = max(ans,i*c+dp[i][j])
print(ans)