main(h1,w1,h2,w2,h3,w3,i)
{
	scanf("%d%d\n%d%d\n%d%d",&h1,&w1,&h2,&w2,&h3,&w3);
	h1=h1*100-w1;
	h2=h2*100-w2;
	h3=h3*100-w3;
	for(i=3;i--;){
		if(h1>h2&&h1>h3){
			puts("A");
			h1=-1;
		}
		if(h2>h1&&h2>h3){
			puts("B");
			h2=-1;
		}
		if(h3>h1&&h3>h2){
			puts("C");
			h3=-1;
		}
	}
}