If the perimeter of a rectangular picture frame is 30 centimeters (cm) and the width is 10 centimeters (cm), how many centimeters (cm) is the length of the picture frame?
30 2 [OP_DIV] 10 [OP_SUB]
var_a = 30
var_b = 2
var_c = var_a / var_b
var_d = 10
var_e = var_c - var_d
print(int(var_e))