a,b,s = map(int, raw_input().split())
if abs(b-s) < abs(a-s):
    d = abs(b-s)
    if a == 0:
        d += s-1
        d += 2
    else:
        d += min(s-1, abs(a-s))
        d += a
else:
    d = abs(a-s)
    d += s
print d