double hanshu(int A);
int main()
{
int inputN;
scanf("%d",&inputN);
double re=0.0;
re = hanshu(inputN);
printf("(%d)!=%f",inputN,re);
return 0;
}
double hanshu(int A)
double re=1.0;;
int i;
for(i = 1;i<=A;i++)
re *=i;
return re;