from collections import defaultdict,deque
import sys,heapq,bisect,math,itertools,string,queue,datetime,random
sys.setrecursionlimit(10**8)
INF = float('inf')
mod = 10**9+7
eps = 10**-7
def inpl(): return list(map(int, input().split()))
def inpls(): return list(input().split())

L,R,M = inpl()

if R-L+1 >= M:
    print(M)
else:
    print(R-L+1)