def largest_triangle(a,b):
    import math
     
    if (a < 0 or b < 0): 
        return -1 
    area = (3 * math.sqrt(3) * pow(a, 2)) / (4 * b);  
    return area 
def largest_triangle(m, b):
    import math
    if m < 0 or b < 0:
       
        return -1
    area = (3 * math.sqrt(3) * pow(m, 2)) / (4 * b)
    return area