def main():
    import sys
    input = sys.stdin.read
    data = input().split()
    
    N = int(data[0])
    V = int(data[1])
    C = int(data[2])
    
    items = []
    idx = 3
    for _ in range(N):
        v = int(data[idx])
        w = int(data[idx + 1])
        items.append((v, w))
        idx += 2
    
    INF = -10**18
    DP = [ [INF] * (N + 2) for _ in range(V + 2) ]
    DP[0][0] = 0  # initial state
    
    for v_i, w_i in items:
        # 0-1 knapsack step: include the item once
        for j in range(V, v_i - 1, -1):
            for k in range(N, -1, -1):
                if DP[j - v_i][k] != INF:
                    new_j = j
                    new_k = k + 1
                    if new_k > N:
                        continue
                    new_sat = DP[j - v_i][k] + w_i + C
                    if new_sat > DP[new_j][new_k]:
                        DP[new_j][new_k] = new_sat
        
        # Unbounded knapsack step: include the item multiple times
        for j in range(V - v_i + 1):
            for k in range(N + 1):
                if DP[j][k] != INF:
                    new_j = j + v_i
                    if new_j > V:
                        continue
                    new_sat = DP[j][k] + w_i
                    if new_sat > DP[new_j][k]:
                        DP[new_j][k] = new_sat
    
    max_sat = 0
    for j in range(V + 1):
        for k in range(N + 1):
            if DP[j][k] > max_sat:
                max_sat = DP[j][k]
    
    print(max_sat)

if __name__ == "__main__":
    main()