import sys

alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"

(a,b,s) = input().split(" ")
a=int(a)
b=int(b)
s=int(s)

da = abs(s-a)
db = abs(s-b)
come_elevator = "a" if (da <= db) or s==1 else "b"
if come_elevator == "a":
    print(da+s)
    exit()
out = da+a if da+a > b+a else b+a
if a == 0:   out = out+1
print(out)