#include <stdio.h>

int main(){
    int brother[3];
    int i, j, max = 0, max_cnt;

    scanf("%d%d%d", &brother[0], &brother[1], &brother[2]);

    for(i = 0; i < 3; i++){
        for(j = 0; j < 3; j++){
            if(max <= brother[j]){
                max = brother[j];
                max_cnt = j;
            }
        }
        if(max_cnt == 0){
            printf("A\n");
        }else if(max_cnt == 1){
            printf("B\n");
        }else if(max_cnt == 2){
            printf("C\n");
        }
        brother[max_cnt] = 0;
        max = 0;
    }

    return 0;

}