#include <iostream>
#include <cmath>
#include <cstdlib>
using namespace std;
long factorial(int a)
{
int i=0;
long sum=1;
if (a==1)
return a;
else
for (i=2;i<=a;i++)
{
sum=sum*i;
}
return sum;
}
int main()
{
int x=0;
int i=0,j=1;
float sum=1;
float s=0;
cin>>x;
for (i=2;;i+=2)
{
//cout<<"循環第"<<i<<"次"<<endl;
s=pow((float)x,i)/factorial(i);
//cout<<s<<endl;
if (s<1e-6)
break;
sum=sum+(-j)*s;
}
cout<<sum<<endl;
return 0;
}