Students are standing in a line at the bus stop. When Minseok is standing 12th from the front and Junho is standing 9th from the back, Junho is standing right behind Minseok. Find the total number of students standing in line at the bus stop.
12 9 [OP_ADD]
var_a = 12
var_b = 9
var_c = var_a + var_b
print(int(var_c))