#include <bits/stdc++.h>

 using namespace std;

 typedef long long LL;

 const int maxn = ;

 int k;

 int digit[maxn];

 LL dp[maxn][][][][];

 LL l, r;

 bool ok(int a, int b, int c, int d, int e) {

     if(k == ) return e != d;

     if(k == ) return e != d && e != c;

     if(k == ) return e != d && e != c && e != b;

     if(k == ) return e != d && e != c && e != b && e != a;

 }

 LL dfs(int l, int p1, int p2, int p3, int p4, bool flag) {

     if(l == ) return p4 != ;

     if(!flag && ~dp[l][p1][p2][p3][p4]) return dp[l][p1][p2][p3][p4];

     LL ret = ;

     int pos = flag ? digit[l] : ;

     for(int i = ; i <= pos; i++) {

         if(i ==  && p4 == ) ret += dfs(l-,,,,,flag&&(i==pos));

         else if(ok(p1,p2,p3,p4,i)) ret += dfs(l-,p2,p3,p4,i,flag&&(i==pos));

     }

     if(!flag) dp[l][p1][p2][p3][p4] = ret;

     return ret;

 }

 LL f(LL x) {

     if(l <= ) return ;

     int pos = ;

     while(x) {

         digit[++pos] = x % ;

         x /= ;

     }

     return dfs(pos,,,,,true);

 }

 int main() {

     // freopen("in", "r", stdin);

     while(~scanf("%I64d%I64d%d",&l,&r,&k)) {

         memset(dp, -, sizeof(dp));

         printf("%I64d\n", f(r)-f(l-));

     }

     return ;

 }