Shalar_kopal

#include<iostream>
#include<vector>
#include<map>
#define ll long long
#define mxn 505
using namespace std;

bool prime[mxn];
vector<int>v;

void sieve(){
    for(int i=0;i<mxn;i++){
        prime[i]=false;
    }
    for(int i=2;i*i<mxn;i++){
        if(prime[i]==false){
            for(int j=i*2;j<mxn;j+=i){
                prime[j]=true;
            }
        }
    }
    for(int i=2;i<mxn;i++){
        if(prime[i]==false){
            v.push_back(i);
        }
    }
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    sieve();

    int n,k;
    while(cin>>n>>k){
        int r=n-k;
        map<int,int>mp;
        int i=0;
        while(v[i]<=n){
            int temp=n;
            while(temp>0){
                temp/=v[i];
                mp[v[i]]+=temp;
            }
            i++;
        }
        i=0;
        while(v[i]<=r){
            int temp=r;
            while(temp>0){
                temp/=v[i];
                mp[v[i]]-=temp;
            }
            i++;
        }
        i=0;
        while(v[i]<=k){
            int temp=k;
            while(temp>0){
                temp/=v[i];
                mp[v[i]]-=temp;
            }
            i++;
        }

        ll ans=1;
        for(int i=0;i<mxn;i++){
                //cout<<mp[i]<<" ";
            ans*=(mp[i]+1);
        }
        cout<<ans<<endl;

    }
return 0;

}