text: #include<stdio.h>
  int main()
  {
  	float n,s=0,i,avg;
  	int count=0;
  	while(1)
  	{
      	A:
  		scanf("%f",&n);
      	{
      		if(n>=0.0&&n<=10.0)
      		{
      			s=s+n;
  				count++;	
      		}
      		if(n<0.0||n>10.0)
  			{
  				printf("nota invalida\n");
  				goto A;
  			}
  		}
      	if(count==2)
  		{
  			break;
  		}
  	}
  	
  	avg=s/2;
  	printf("media = %.2f\n",avg);
  	
  	return 0;	
  }
  