import sys
readline = sys.stdin.readline

def f(n, v, k):
    return k + 2 * v + n * 2 * (V + 1)


N, V, C = map(int, readline().split())
v, w = [0] * N, [0] * N
for i in range(N):
    v[i], w[i] = map(int, readline().split())
    
inf = 10 ** 18
dp = [-inf] * (2 * (V + 1) * (N + 1))
dp[0] = 0
for i in range(N):
    for j in range(V + 1):
        dp[f(i + 1,j,0)] = max(dp[f(i + 1,j,0)], dp[f(i,j,0)], dp[f(i,j,1)])
        if j - v[i] >= 0:
            dp[f(i + 1,j,1)] = max(dp[f(i+1,j,1)], dp[f(i+1,j-v[i],0)] + w[i] + C)
            dp[f(i + 1,j,1)] = max(dp[f(i+1,j,1)], dp[f(i+1,j-v[i],1)] + w[i])
            
ans = 0
for i in range(V + 1):
    ans = max(ans, dp[f(N,i,0)], dp[f(N,i,1)])
    
print(ans)