fibonacci avec memoïsation

map = new Map()
f = (n) =>
{
    if(n <= 2)
        return 0
    if(n == 3)
        return 1


    if(!map.get(n))
    {
        x = f(n-1)+f(n-2)+f(n-3)+f(n-4)
        map.set(n,x)
        return x
    }

    else return map.get(n)

}
let n = readline()-1
t = []
for(i = 0; i <= n; i++)
    t.push(f(i))
//print(t)

console.log(t.reduce((m,n)=>m+n,0))