M - n-divisors

#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;
#define maxSz 10e7
vector<int>divisors(maxSz);
void Divisor(int n)
{
    for(int i=1;i<=n;i++)for(int j=i;j<=n;j+=i)divisors[j]++;
    return;
}
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    #ifndef ONLINE_JUDGE
    freopen("input.cpp","r",stdin);
    //freopen("output.cpp","w",stdout);
    #endif // ONLINE_JUDGE
    ll a,b,n,cnt=0;
    cin>>a>>b>>n;
    if(a>b)swap(a,b);
    Divisor(b);
    for(int i=a;i<=b;i++)if(divisors[i]==n)cnt++;
    cout<<cnt<<endl;
    return 0;
}