#include <bits/stdc++.h>
using namespace std;
int n,k,a[105]={1},total=0;
void dfs(int k,int sum){
    for(int i=a[sum-1];i<=k;i++){
        if(i<n){
            a[sum]=i;
            k-=i;
            if(k==0&&sum==3) total++;
            else dfs(k,sum+1);
            k+=i;
        }
    }
}
int main()
{
    cin>>n>>k;
    dfs(n,1);
    cout<<total;
    return 0;
}