数数字

 

//n位数中有几个m?

 

#include<cstdio>
int a[10]={0,1,20,300,4000,50000,600000,7000000,80000000,900000000};
int n,m;
int main(){
    scanf("%d%d",&n,&m);
    printf("%d\n",m?a[n]-a[n-1]:9*a[n-1]);
    return 0;
}