#include <bits/stdc++.h>
#define rep(i, n) for(int i = 0; i < n; i++)
using namespace std;
using ll = long long;
using P = pair<int, int>;

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

int main(){
  	string s;
  	int K;
  	cin >> s >> K;
  	
  	int n = s.size();
  	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];
        }
    }
  	int ans = dp[n][K][0] + dp[n][K][1];
  	cout << ans << endl;
}