pls how do i find the ans

Question

The Snail in the Well

The snail climbs up 7 feet each day and slips back 2 feet each night.
How many days will it take the snail to get out of a well with the given depth?

Sample Input:
31

Sample Output:
6

Explanation: Let's break down the distance the snail covers each day:
Day 1: 7-2=5
Day 2: 5+7-2=10
Day 3: 10+7-2=15
Day 4: 15+7-2=20
Day 5: 20+7-2=25
Day 6: 25+7=32
So, on Day 6 the snail will reach 32 feet and get out of the well at day, without slipping back that night.

this is my code
function main() {
var depth = parseInt(readLine(), 10);
//your code goes here
var a = depth/5
var b = depth%5
var c = b*0.1
var d = a - c
console.log(d);
}

plssssss help me

Answer 1

* Read the problem and explanation of the example answer carefully

* Write down the main steps you'll need as comments in your code before you start coding

* I don't really see where you're going with the approach you've shown - especially var c, so I recommend starting again

* You might want to try using a loop

* This time please don't name your variables things like a, b, c etc. Give them meaningful names.