问此`do..while`循环不起作用

EN

int sc1,sc2,a=0,b=0;

do
{

 printf("Give the scores\n");

 scanf("%d %d", &sc1,&sc2);

 //===============================================

 if (sc1 > sc2)     
   a+=1;
 else if (sc1<sc2)
   b+=1;
 else if (sc1==sc2)
   printf("tie\n");

 //===============================================

 if (a>b)    
    printf("team 1 is in the lead\n");
 else if (a<b)
    printf("team 2 is in the lead\n");
 else if (b==a)
    printf("tie\n");      

}
while((a==3) || (b==3));

//===============================================


if (a==3)
  printf("team 1 got the cup");
else
  printf("team 2 got the cup");