#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0;i<n;i++)
typedef vector<int> vec;

int dp[105][4][2];

int main(){
  string s; cin>>s;
  int n=s.size();
  int K; cin>>K;
  dp[0][0][0]=1;
  
  rep(i,n)rep(j,4)rep(k,2){
    int nd=s[i]-'0';
    rep(d,10){
      int ni=i+1,nj=j,nk=k;
      if(d!=0)nj++;
      if(nj>K)continue;
      if(k==0){
        if(d>nd)continue;
        if(d<nd)nk=1;
      }
      dp[ni][nj][nk]+=dp[i][j][k];
    }
  }
  cout<< dp[n][K][0]+dp[n][K][1]<<endl;
}
