from sys import stdin

N,V,C = map(int,stdin.readline().split())

dp = [float("-inf")] * (V+1)
dp[0] = 0

for i in range(N):

    v,w = map(int,stdin.readline().split())
    for i in range(V-v,-1,-1):

        dp[i+v] = max(dp[i+v] , dp[i] + C + w)

    for i in range(V-v+1):
        dp[i+v] = max(dp[i+v] , dp[i] + w)

print (max(dp))