niggest rises

#include <iostream>
using namespace std;

int raw_digits(int x);
int central_digit(int x);

int main() {
    int n;
    cin >> n;
    int i = 0;
    bool winner = false;
    bool first = true;
    int x, m;
    while ((cin >> x) and (i < 2*n) and (!winner)) {
        ++i;
        if (x > 9 and raw_digits(x)%2 == 0) winner = true;
        else if (first) {
            first = false;
            m = central_digit(x);
        }
        if (m != central_digit(x)) winner = true;
    }
    if (!winner) cout << "=" << endl;
    else if (i%2 == 0) cout << "A" << endl;
    else cout << "B" << endl;
}

int raw_digits(int x) {
    int i = 0;
    while (x > 0) {
        x /= 10;
        ++i;
    }
    return i;
}

int central_digit(int x) {
    if (x < 10) return x;
    int i = 1;
    int n = raw_digits(x)/2 + 1;
    while (i < n) {
        x /= 10;
        ++i;
    }
    x %= 10;
    return x;
}