Codeforces Round #518 (Div. 2) [Thanks, Mail.Ru!]
B. LCM
Ivan has number bb. He is sorting through the numbers aa from 11 to 10181018, and for every aa writes [a,b]a[a,b]a on blackboard. Here [a,b][a,b] stands for least common multiple of aa and bb. Ivan is very lazy, that's why this task bored him soon. But he is interested in how many different numbers he would write on the board if he would finish the task. Help him to find the quantity of different numbers he would write on the board.
Input
The only line contains one integer — bb (1≤b≤1010)(1≤b≤1010).
Output
Print one number — answer for the problem.
Examples
input
1
output
1
input
2
output
2
Note
In the first example [a,1]=a[a,1]=a, therefore [a,b]a[a,b]a is always equal to 11.
In the second example [a,2][a,2] can be equal to aa or 2⋅a2⋅a depending on parity of aa. [a,b]a[a,b]a can be equal to 11 and 22.
ANALYSIS:
轉化為一個N的所有因子個數。
AC_CODE:
#include<bits\stdc++.h> using namespace std; long long n, ans; int main() { cin >> n; for (long long int i = 1; i*i <= n; i++) { if (n%i == 0) { ans += 2; } if (i*i == n) ans--; } cout << ans << endl; }