N,V,C = map(int,input().split())
g = [list(map(int,input().split())) for _ in range(N)]

dp = [[0] * (V+1) for _ in range(N+1)]

for i in range(N):
    vi,wi = g[i]
    for j in range(V+1):
        if j-vi >= 0:
            dp[i+1][j] = max(dp[i][j-vi] + wi + C , dp[i][j] , dp[i+1][j-vi] + wi)
        else:
            dp[i+1][j] = dp[i][j]

print(max(dp[N]))