import sys
input = sys.stdin.readline

N,V,C=map(int,input().split())
AB=[tuple(map(int,input().split())) for i in range(N)]

DP=[0]*(V+1)

for a,b in AB:
    for i in range(V,-1,-1):
        if i>=a:
            DP[i]=max(DP[i],DP[i-a]+b+C)

    for i in range(V+1):
        if i>=a:
            DP[i]=max(DP[i],DP[i-a]+b)

print(max(DP))