#include <stdio.h>
//s=1-3+5-7+....-99+101
main()
{
int i,t=1,s=0;
for(i=1;i<=101;i+=2)
{
t=t*i;
s=s+t;
t=-t/i;
}
printf("%d\n",s);
getchar();
}
#include <stdio.h>
//s=1-3+5-7+....-99+101
main()
{
int i,t=1,s=0;
for(i=1;i<=101;i+=2)
{
t=t*i;
s=s+t;
t=-i/t;
}
printf("%d\n",s);
getchar();
}