# PROBLEM LINK:

**Author:** Ishpreet

**Tester:** Karan

# DIFFICULTY:

SIMPLE

### PROBLEM:

There are total N stairs. A person climbs A stairs upwards in day and comes downstairs in night by B stairs. Find number of days person will take to reach the top of staircase.

### EXPLANATION:

Let us start by solving the problem day wise.

Day1: A Night1: A-B

Day2: (A-B)+A Night2: 2*(A-B)

Day3: 2*(A-B)+A Night3: 3(A-B)

…

DayX: (A - B) * (X - 1) + A,

Let us assume, on day X, he crossed N stairs.

So,

(A - B) * (X - 1) + A >= N

AX - BX + B >= N

X (A - B) >= N - B

X >= (N - B) / (A - B)

All we need is the integer value of X which is >= (N - B) / (A - B).