#include <stdio.h>
#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf 1000000005


int main(){
	
	vector<long double> num(150,0.0);
	
	rep(i,150){
		if(i<=1)continue;
		
		for(int j=1;j<=100000;j++){
			num[i] += 1.0 / pow(j,i);
		}
		num[i] -= 1.0;
	}
	
	int x;
	cin>>x;
	
	long double ans = 0.0;
	
	for(int i=x;i<150;i++){
		ans += num[i];
	}
	
	ans *= 1000000.0;
	
	cout<<floor(ans)<<endl;
	
    return 0;
}