#include <stdio.h>

int main()
{
  int amount;
  int result = 10;
  printf("please enter amount\n");
  scanf("%d", &amount);

  printf("current values: amount = %d, result = %d\n", amount, result);
  if (amount == 10)
  {
    result = amount;
  }
  else if (amount == 20)
  {
    result = amount * amount;
  }
  else if (amount == 30)
  {
    result = 1000 + amount;
  }
  else 
  {
    result = 0;
  }

  printf("result = %d\n", result);
}