#include<stdio.h>
int main()
{
int n;
double sum=0.0;
int sign=1;
scanf("%d",&n);
for(n=1;n<=100;n++)
{
sum+=1.0/n*sign;
sign=-sign;
}
printf("%f",sum);
}
#include<stdio.h>
int main()
{
int n;
double sum=0.0;
int sign=1;
scanf("%d",&n);
for(n=1;n<=100;n++)
{
sum+=1.0/n*sign;
sign=-sign;
}
printf("%f",sum);
}