#include <stdio.h>

int height = 0; // = height of stair case
int numBricks = 0; // = num bricks needed to build staircase


void c_tri()
{
	numBricks = height * (height + 1) / 2;
}

void asm_tri()
{
	asm("push eax \n\t"
	    "push ebx \n\t"
	    "push edx \n\t"

	    "mov ebx, 2 \n\t"
	    "mov eax, _height \n\t"
	    "add eax, 1 \n\t"
	    "mul DWORD PTR _height \n\t"
	    "div DWORD PTR ebx  \n\t"
	    "mov _numBricks, eax \n\t"

	    "pop edx \n\t"
	    "pop ebx \n\t"
	    "pop eax");
}


int main(void)
{
	while(1)
	{
		printf("-> ");
		scanf("%d", &height);
		if (height < 0) break;
		asm_tri();
		printf("%d\n", numBricks);
	}
	printf("bye\n");
	return 0;
}