#include <stdio.h>
int main()
{
long a,b,c,sum;
while(scanf("%d %d %d",&a,&b,&c)!=EOF)
{
sum=0;
if(a>b || b>c)
{sum=b+c;
if(a>sum)
printf("A\n");

else
printf("B\n");
}

else if(b>a || a>c)
{sum=a+c;
if(b>sum)
printf("B\n");

else
printf("A\n");
}

else if(c>a || a>b)
{sum=a+b;
if(c>sum)
printf("C\n");

else
printf("A\n");
}

else if(a>c || c>b)
{sum=c+b;
if(a>sum)
printf("A\n");

else
printf("C\n");
}

else if(b>c || c>a)
{sum=c+a;
if(b>sum)
printf("B\n");

else
printf("C\n");

}
else if(c>b || b>a)
{
sum=b+a;
if(c>sum)
printf("C\n");

else
printf("B\n");
}


}

}