#include
#include
double fun(double x,double eps){
double sum=1.0,m=1.0,t;
int i=1;
do{
m=m*i;
t=pow(x,1)/m;
sum+=t;
i++;
}while (t>eps);
return sum;
}
void main()
{
printf("%f",fun(1,1e-6));
}