a, b, s =  [ int(v) for v in input().split() ]

if s == 1:
    ans = abs(s-a)+1
else:
    dsa = abs(s-a)
    dsb = abs(s-b)
    if dsa <= dsb:
        ans = dsa + s
    else:
        if a == 0:
            dsb + s + 1
        else:
            ans = dsa + dsb + a



print(ans)