import sys
#input = sys.stdin.readline
input = sys.stdin.buffer.readline #文字列はダメ
#sys.setrecursionlimit(1000000)
#import bisect
#import itertools
#import random
#from heapq import heapify, heappop, heappush
#from collections import defaultdict 
#from collections import deque
#import copy
#import math
#from functools import lru_cache
#@lru_cache(maxsize=None)
#MOD = pow(10,9) + 7
#MOD = 998244353
#dx = [1,0,-1,0]
#dy = [0,1,0,-1]
#dx8 = [1,1,0,-1,-1,-1,0,1]
#dy8 = [0,1,1,1,0,-1,-1,-1]


def main():
    N,V,C = map(int,input().split())
    v = []; w = []
    for i in range(N):
        vi,wi = map(int,input().split())
        v.append(vi)
        w.append(wi)
    
    # dp[j]: i番目まで見てj円使った時の価値の最大値
    dp = [0]*(V+1)
    for vi,wi in zip(v,w):
        #配るDP
        #初めての商品は1回だけ。そのため実家DP
        for j in reversed(range(V)):
            if j+vi <= V:
                dp[j+vi] = max(dp[j+vi], dp[j] + wi+C)
        #2個目以降はいくらでも
        for j in range(V):
            if j+vi <= V:
                dp[j+vi] = max(dp[j+vi], dp[j] + wi)
    
    ans = max(dp)
    print(ans)



if __name__ == '__main__':
    main()