#include <stdio.h>
#include <string.h>

int main()
{
while (1)
{

unsigned int vote[3];
int max = 0;
int min = 0;
memset(vote,0,sizeof(vote));

for ( int i = 0 ; i < 3 ; i++)
{
scanf("%d",&vote[i]);
if ( vote[max] < vote[i] ) max = i;
if ( vote[min] > vote[i] ) min = i;
}

int mid = 3-min-max;
vote[mid] += vote[min];
if ( vote[mid] > vote[max] ) printf("%c\n",mid + 65);
else printf("%c\n",max + 65);

}
return 0;
}

//印出來要大寫