input_line = input().rstrip().split(" ")
X = int(input_line[0])
Y = int(input_line[1])
Z = int(input_line[2])
num = 0

for i in range(Z):
    num = num + 1
if num >= X:
    num = num - 1
elif num >= Z:
    num = num - 2
print(num)