#include <iostream> using namespace std; int main() { int a,b=1,j=1; double e=1.0; cin>>a; for(int i=1,i<=a,i=i+1){ j=i; while(j!=0){ b=b*j; j=j-1; } e=e+1.0/b; b=1; } cout<<e; return 0; }