Codeforces 495B – Modular Equations

This is a very interesting divisor count problem.

```
/*
User ID: Tanmoy_Datta
*/

#include &lt;bits/stdc++.h&gt;

#define pii pair &lt;int,int&gt;
#define sc scanf
#define pf printf
#define Pi 2*acos(0.0)
#define ms(a,b) memset(a, b, sizeof(a))
#define pb(a) push_back(a)
#define MP make_pair
#define oo 1&lt;&lt;29
#define dd double
#define ll long long
#define EPS 10E-10
#define ff first
#define ss second
#define MAX 10000
#define SZ(a) (int)a.size()
#define getint(a) scanf(&quot;%d&quot;,&amp;a)
#define loop(i,n) for(int i=0;i&lt;n;i++)
#define all(a) a.begin(),a.end()
#define intlim 2147483648
#define inf 1000000
#define rtintlim 46340
#define llim 9223372036854775808
#define rtllim 3037000499
#define ull unsigned long long
#define I int

using namespace std;

/* Bits operation */
int Set(int n,int pos)  { return n = n | 1&lt;&lt;pos;}
bool check(int n,int pos) { return n &amp; 1&lt;&lt;pos;}
int Reset(int n, int pos) { return n=n &amp; ~(1&lt;&lt;pos);}

int main()
{
///freopen(&quot;in.txt&quot;,&quot;r&quot;,stdin);
///freopen(&quot;out.txt&quot;,&quot;w&quot;,stdout);
ll a,b;
cin&gt;&gt;a&gt;&gt;b;
if(a==b)
cout&lt;&lt;&quot;infinity&quot;&lt;&lt;endl;
else
{
a-=b;
int ans=0;
for(int i=1;i*i&lt;=a;i++)
{
if(a%i==0)
{
if(i&gt;b)
ans++;
if(a/i!=i &amp;&amp; (a/i)&gt;b)
ans++;
}
}
cout&lt;&lt;ans&lt;&lt;endl;
}
return 0;
}

```