#include<stdio.h>
int CountDivisible(int value, int divisor){
    if(divisor==0){
        return 0;
        
    }
    int count=(value-1)/divisor;
    return count;
}
inrt main()
{
    int value divisor;
    if(scanf("%d %d", &value,&divisor)==2){
        int result=CountDivisible(value,divisor);
        printf("%d\n",result);
    }
    return 0;
}