#include <stdio.h>
#include <stdlib.h>
#define EPS 1e-5
int main(int argc, char *argv[])
{
unsigned int k=1;
double x,a,s;
printf("vvedite x=");
scanf("x=",&x);
a=(x-1)/1;
s=a;
while( a>EPS || a<-EPS)
{
k++;
a*=(x-k)/(k*(x-k+1));
s+=a;
}
printf("%lf\n", s);
system("PAUSE");
return 0;
}