#include <stdio.h>

int main() {
    int count[3]={0,0,0};
    
    for (int j=0; j<3; j++)
    {
        for (int i=0; i<4; i++)
        {
            int temp;
            scanf("%d",&temp);
            if(temp == 0)
                count[j]++;
        }
    }
    for (int j=0; j<3; j++)
    {
        switch (count[j]) {
            case 0:
                printf("E");
                break;
            case 1:
                printf("A");
                break;
            case 2:
                printf("B");
                break;
            case 3:
                printf("C");
                break;
            case 4:
                printf("D");
                break;
            default:
                break;
        }
        printf("\n");
    }
    return 0;
}