N,V,C = map(int,input().split())
A = [0]+[list(map(int,input().split())) for _ in range(N)]
INFTY = 10**9
dp = [[[0 for _ in range(2)] for _ in range(V+1)] for _ in range(N+1)]
for j in range(V+1):
    if j<A[1][0]:
        dp[1][j][1] = -INFTY
    else:
        k = j//A[1][0]
        dp[1][j][1] = k * A[1][1]+C
for i in range(2,N+1):
    for j in range(V+1):
        dp[i][j][0] = max(dp[i-1][j][0],dp[i-1][j][1])
        if j>=A[i][0]:
            dp[i][j][1] = max(dp[i][j-A[i][0]][0]+A[i][1]+C,dp[i][j-A[i][0]][1]+A[i][1])
print(max(dp[N][V][0],dp[N][V][1]))