def main():
    import sys
    input = sys.stdin.read().split()
    idx = 0
    N = int(input[idx]); idx +=1
    V = int(input[idx]); idx +=1
    C = int(input[idx]); idx +=1

    types = []
    for _ in range(N):
        v = int(input[idx]); idx +=1
        w = int(input[idx]); idx +=1
        types.append((v, w))

    # Initialize DP
    dp = [-float('inf')] * (V + 1)
    dp[0] = 0

    for v_i, w_i in types:
        # Step 1: 0-1 step (activate the type)
        for c in range(V, v_i - 1, -1):
            if dp[c - v_i] != -float('inf'):
                if dp[c] < dp[c - v_i] + w_i + C:
                    dp[c] = dp[c - v_i] + w_i + C

        # Step 2: Unbounded step (additional items)
        for c in range(v_i, V + 1):
            if dp[c - v_i] != -float('inf'):
                if dp[c] < dp[c - v_i] + w_i:
                    dp[c] = dp[c - v_i] + w_i

    max_satisfaction = 0
    for c in range(V + 1):
        if dp[c] > max_satisfaction:
            max_satisfaction = dp[c]

    print(max_satisfaction)

if __name__ == "__main__":
    main()