>>27
#include <stdio.h>
#include <stdlib.h>
double f(int n, int i, double x)
{
if (n<=1) return 1; else return 1 - x * x / i / (i+1) * f(n-1, i+2, x);
}
double sin_n(int n, double x)
{
return f(n, 2, x) * x;
}
int main()
{
char buf[100];
while (fgets(buf, sizeof(buf), stdin)) {
double x = atof(buf);
printf("sin_10=%f\n", sin_n(10, x));
}
return 0;
}