# -*- coding: utf-8 -*-
import sys, time
 
 
def fnc(A, B, P):
    #t1 = time.time()
    zx = [0] * 1030
    for i in range(A,B+1):
        su, wu = 0, i
        while wu >0:
            #wu, tmp = divmod(wu, 10)
            su |= 1<<(wu%10);
            wu //=10
        zx[su] +=1
    pcnt = [0] * 1030;
    for i in range(1024):
        pcnt[i] = bin(i).count('1')
    ans = 0
    for i in range(1024):
        for j in range(i):
            #if  bin(i|j).count('1')  == P:
            if  pcnt[i|j]  == P:
                ans += zx[i] * zx[j]
        if pcnt[i] == P:
            ans += zx[i] * (zx[i]-1) >>1
    #print("%fs" %(time.time() - t1))
    return ans
 
for line in sys.stdin:
    A, B, P = map(int, line.rstrip().split())
    print("%d %d %d --> %d" %(A,B,P,fnc(A,B,P)))
 

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10 1000 5      
44 44444 4     
56785 113452 1 
102345 480713 6
1 500000 7