#include<stdio.h>
#include<math.h>
int enter()
{
	int n;
	do{
		printf("Enter n: ");
		scanf("%d",&n);
	}while(n<1);
	return n;
}
float sum_f(int n)
{
	int i,gt=1;
	float f=0;
	for(i=1; i<=n; i++)
	{
		gt=gt*i;
		f=f+1.0/gt;
	}
	return f;
}
main()
{
	int n;
	float f;
	n=enter();
	f=sum_f(n);
	printf("Sum of part A is %f",f);
}