#include<iostream>

using namespace std;

int main(){
    int input;
    cin >> input;
    int max = 1;
    int count = 0;
    for(int i=0;i<input;i++){
        max *= 10;
    }
    for(int i=0;i<max;i++){
        if(i>6 && i%7==0)count++;
    }
    cout << (double)count/max << endl;
    return 0;
}