A stone that is 30 meters (m) high from the ground is said to fall at 1 meter (m) per second, and a stone 20 meters (m) high from the ground is said to fall at 0.5 meters (m) per second. Find the height of the two stones when they are at the same height.
30 30 20 [OP_SUB] 1 0.5 [OP_SUB] [OP_DIV] [OP_SUB]
var_a = 30
var_b = 30
var_c = 20
var_d = var_b - var_c
var_e = 1
var_f = 0.5
var_g = var_e - var_f
var_h = var_d / var_g
var_i = var_a - var_h
print(int(var_i))