import sys
readline = sys.stdin.readline


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 for i in range(V + 1) ] for j in range(N + 1)]
dp[0][0][0] = 0
for i in range(N):
    for j in range(V + 1):
        dp[i + 1][j][0] = max(dp[i + 1][j][0], dp[i][j][0], dp[i][j][1])
        if j - v[i] >= 0:
            dp[i + 1][j][1] = max(dp[i + 1][j][1], dp[i + 1][j - v[i]][0] + w[i] + C)
            dp[i + 1][j][1] = max(dp[i + 1][j][1], dp[i + 1][j - v[i]][1] + w[i])
            
ans = 0
for i in range(V + 1):
    ans = max(ans, dp[N][i][0], dp[N][i][1])
    
print(ans)