### PROBLEM LINK:

**Author:** Sudhanshu Gupta

**Tester:** Sudhanshu Gupta

**Editorialist:** Sudhanshu Gupta

### DIFFICULTY:

HARD

### PREREQUISITES:

Math

### PROBLEM:

For a given positive integer N find the number of all pairs (a, b) of positive integers such that 1 <= a < b <= N and the sum a + b divides the product a * b.

### EXPLANATION:

### SOLUTIONS:

Solution can be found here.