#include <iostream>
#include <algorithm>
#include <cstring>
#include <cstdio>
typedef long long ll;
using namespace std;

int tark,maxlen;
string A,B;
ll f[22][2][2][2][1<<10];

inline int GetLength(int k)
{
   int len = 0;
   for(int i = 0 ; i < 10 ; ++ i)
    if (k >> i & 1)
     len++;
   return len;
}

inline int tanxinset(int k,int pos) //贪心维护 
{
   for(int i = pos ; i < 10 ; ++ i)    
    if (k >> i & 1)
     return (k & ~(1 << i) ) | (1 << pos);
   return k | (1 << pos);
}

ll dp(int cur,int f1,int f2,int f3,int k)
{
   if (f[cur][f1][f2][f3][k] != -1)
    return f[cur][f1][f2][f3][k];
   ll &ans = f[cur][f1][f2][f3][k] = 0;
   if (cur == maxlen)
    {
       int len =  GetLength(k);
       if (len == tark)
        return ans = 1;
       else
        return ans = 0;
    }
   int st = f1?0:A[cur]-‘0‘;
   int ed = f2?9:B[cur]-‘0‘;
   for(int i = st ; i <= ed ; ++ i)
    {
      if (f3 && i == 0) //拥有前导零,这个不算上升的 
       ans += dp(cur+1, f1 | i > A[cur]-‘0‘ , f2 | i < B[cur]-‘0‘ , f3 & !i, 0 );  
      else
       ans += dp(cur+1, f1 | i > A[cur]-‘0‘ , f2 | i < B[cur]-‘0‘ , f3 & !i, tanxinset(k,i)  ); 
    }
   return ans;
}


int main(int argc,char *argv[])
{
  std::ios::sync_with_stdio(false);
  std::cin.tie(0);
  int Case;
  cin >> Case;
  while(Case--)
   {
         cin >> A >> B >> tark;
         memset(f,-1,sizeof(f));
         maxlen = B.size();
         while(A.size() != maxlen)
          A = ‘0‘ + A;
         printf("%lld\n",dp(0,0,0,1,0));
   }
  return 0;
}