#include <stdio.h>
#include <math.h>

int x,n,i;
int s, ar, pa, k, l;
int main()

{printf("x="); scanf("%d", &x);

ar=1;
pa=1;
k=2;
l=1;
s=1;

if (2<=n<=10);

{for (i=1;i<=n;i++)
  ar=ar*(pow(x,2));
  pa=pa*(k-1)*k;
  k=k+2;
  l=-l;
  s=s+l*(ar/pa);
}
printf("s=%d\n",s);

return 0;
}