题解 | #竞选社长#

int main() {
    char n;
    int a = 0, b = 0;
    while (scanf("%c", &n) != EOF) {
        if (n == '0') break;
        if (n == 'A') a++;
        else b++;
    }
    if (a > b) printf("A");
    else if (a < b) printf("B");
    else printf("E");
    return 0;
}