let input = [

    '4',
    '3'


];




let print = this.print || console.log;
let gets = this.gets || ((arr, index) => () => arr[index++])(input, 0);


//  S = 1 + 1!/x + 2!/x2 + … + N!/xN.

//   n! = n * (n-1)!

//  n! = 1 if n = 0 or n = 1


let N = Number(gets());

let x = Number(gets());

let factoriel = 1;

let sum = 0;

let sum2 = 0;


for (let i = 1; i <= N; i++) {

    factoriel *= i;

}


console.log(factoriel);

sum += 1 + 1 / x + 2 / Math.pow(x, 2) + factoriel / Math.pow(x, N);


print(sum.toFixed(5));