#include <iostream>

 #include <cstdio>

 #include <algorithm>

 #include <cstring>

 #include <cmath>

 #include <cstdlib>

 #include <cctype>

 #include <queue>

 #include <stack>

 #include <map>

 #include <vector>

 #include <set>

 #include <utility>

 #define ll long long

 #define inf 0x3f3f3f3f

 using namespace std;

 const int N=1e6+;

 bool book[N];

 vector<int> prime;

 void get_prime() //筛法预处理素数表

 {

     fill(book,book+N,false);

     for(int i=;i<N;i++)

     {

         if(!book[i])

         {

             prime.push_back(i);

             for(int j=i+i;j<N;j+=i)

                book[j]=true;

         }

     }

 }

 int main()

 {

     //freopen("input.txt","r",stdin);

     get_prime();

     int n,m;

     while(scanf("%d%d",&n,&m)&&n&&m)

     {

         int res=;

         int len=prime.size();

         for(int i=;i<len&&prime[i]<=n;i++)

         {       //分别计算n!、m!、(n-m)! 中含有质因子prime[i]的个数,再把n!的个数减去m!和(n-m)!的个数

             int tn=n,tm=m,tt=n-m,cnt=;

             while(tn)

             {

                 cnt+=tn/prime[i];

                 tn/=prime[i];

             }

             while(tm)

             {

                 cnt-=tm/prime[i];

                 tm/=prime[i];

             }

             while(tt)

             {

                 cnt-=tt/prime[i];

                 tt/=prime[i];

             }

             if(cnt) res++;

         }

         printf("%d\n",res);

     }

     return ;

 }