As Yoojung gave 7 candies to her older sister and 6 to her younger sister, there were 15 left on hand. Find number of candies Yoojung had at first.
15 6 [OP_ADD] 7 [OP_ADD]
var_a = 15
var_b = 6
var_c = var_a + var_b
var_d = 7
var_e = var_c + var_d
print(int(var_e))