#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<math.h>






int main(void){
long long int n,m;
scanf("%lld",&n);
scanf("%lld",&m);
if(n<=999){printf("0\n");}
else if((n%m==(long long int)0)){printf("%.0lld",(long long int)n/m);}
else{printf("%.0lld\n",(long long int)n/m-n%m);}

}