sum

//"Calculate 1 + 1!/X + 2!/X^2 + … + N!/X^N");
let input =['3','2'];
let print = this.print || console.log;
let gets = this.gets || ((arr, index) => () => arr[index++])(input, 0);
let n = Number(gets());
let x = Number(gets());
let result = 1;
let ifac = 1;
for (let i = 1; i <= n; i++)
{
    ifac = 1; //This line is very important
    for (let j = i; j >= 1; j--)
    {
        ifac *= j;
    }
    result += ifac / Math.pow(x, i);
}
print(result.toFixed(5));