TASK

Problem

#10

Given circle radius `r`, use π = 3.14 and print the area `πr²`.

EXAMPLE

Example

Input

5

Output

78.5

LIMITS

Constraints

All numeric input values fit in JavaScript `Number`.

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LEARN Theory for this problem

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### Circle Area

JavaScript arithmetic works with numeric values stored in variables. A clear solution reads the needed values, computes the formula with `+`, `-`, `*`, `/` or `**`, and prints only the final result.

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NEED HELP? Hints

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['Write the formula using named intermediate values if it contains more than one operation.', 'Match each input value type to the operation performed on it: JavaScript string and numeric behavior differ significantly.']

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ANSWER Solution

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const fs = require('fs');
const input = fs.readFileSync(0, 'utf8').trimEnd();
let r = Number(input);
let result = ((3.14) * (r ** 2));
console.log(Object.is(result, 0) ? '0.0' : result);