#include<stdio.h>
int main(void){
    int a,answer=0;
    int i;
    scanf("%d",&a); 
    if(a%2==0){
    for(i=1;i<=a;i++){
      if(i%2==0)
         answer += i;
        
    
    }
    }
    else{
        for(i=1;i<=a;i++){
         if(i%2==1)
             answer += i;
            
        }
    }

    printf("%d\n",answer*a);
    return 0;
}