def main():
    import sys
    input = sys.stdin.read().split()
    idx = 0
    N = int(input[idx]); idx +=1
    M = int(input[idx]); idx +=1
    K = int(input[idx]); idx +=1
    L = int(input[idx]); idx +=1
    
    edges = []
    for _ in range(L):
        X = int(input[idx]); idx +=1
        Y = int(input[idx]); idx +=1
        Z = int(input[idx]); idx +=1
        weight = 1 << Z  # 2^Z
        edges.append((-weight, -Y, -X))  # Negative for descending sort
    
    # Sort by weight descending, then Y descending, then X descending
    edges.sort()
    
    buyer_used = [False] * (N + 1)
    item_used = [False] * (M + 1)
    total = 0
    
    for edge in edges:
        weight_neg, y_neg, x_neg = edge
        weight = -weight_neg
        Y = -y_neg
        X = -x_neg
        if not buyer_used[X] and not item_used[Y]:
            total += weight
            buyer_used[X] = True
            item_used[Y] = True
    
    print(total)

if __name__ == '__main__':
    main()