C++ :

#include<bits/stdc++.h>
using namespace std;
int n,k,ans,z;
int main()
{
    cin>>n>>k;
    for (int i=1;i<=k;i++)z+=i;
    for (int i=1;i<=n-k;i++)
    {
        z+=k;
//        cout<<z<<endl;
        if (floor(sqrt(z))==sqrt(z))ans+=1;
    }
    cout<<ans;
    return 0;
}

Pascal :

 var
    n, k, sum, i, t, ct:longint;
begin
 
   readln(n,k);
 
    sum := 0;
    ct := 0;
    for i := 1  to k do 
        sum := sum + i;
    t := trunc(sqrt(sum));
    if t * t = sum then
        inc(ct);
    for i := 2  to  n - k + 1 do
    begin
        sum := sum+ k;
        t := trunc(sqrt(sum));
        if t * t = sum then
            inc(ct);
    end;
     writeln(ct);
end.