n, v, c = map(int, input().split())
VW = [list(map(int, input().split())) for _ in range(n)]

INF = 10**18
DP = [[-INF for _ in range(v + 1)] for _ in range(n + 1)]
DP[0][0] = 0
for i in range(n):
    cv, cw = VW[i]
    for j in range(v + 1):
        if j >= cv:
            DP[i + 1][j] = max(DP[i + 1][j], DP[i][j], DP[i][j - cv] + cw + c)
        else:
            DP[i + 1][j] = max(DP[i + 1][j], DP[i][j])
    for j in range(cv, v + 1):
        DP[i + 1][j] = max(DP[i + 1][j], DP[i + 1][j - cv] + cw)
print(max(DP[-1]))