why there has an error i tried so many time

Question

#Function is defined
def eq1( vi, t, a):
d = vi * t + 1/2*a* t**2

print ("The Distance Travelled is ",d)

#float type Values are taken from the user 
val1 = float(input("Enter the initial velocity: "))

val2 = 15

val3 = float(input("Enter the acceleration : "))

#function eq1 is called which returns a value 'd' calculated according to the equation eq1(val1,val2.val3)

File "<ipython-input-4-a696fb5b84fa>", line 3
    d = vi * t + 1/2*a* t**2
    ^
IndentationError: expected an indented block