data_n = input()

data_s = data_n.split(" ")
Low_n = int(data_s[0])
Rarge_n = int(data_s[1])
M_n = int(data_s[2])
result = 0


for data_M in range(M_n):
	if Low_n <= Rarge_n:
		result = result+1
		Low_n = Low_n+1
	elif result > M_n:
		result = M_n
		break

print(result)