// #pragma GCC target("avx2,avx512f,avx512vl,avx512bw,avx512dq,avx512cd,avx512vbmi,avx512vbmi2,avx512vpopcntdq,avx512bitalg,bmi,bmi2,lzcnt,popcnt")
// #pragma GCC optimize("Ofast")

#include<bits/stdc++.h>
using namespace std;

signed main() {
    ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);

    string s;
    cin >> s;
    int n = s.size();
    string a = s.substr(0, n / 2);
    string b = s.substr(n/2, n / 2);

    int sum = 0;
    for (auto& i : a) {
        sum += (i - 'A');
    }

    for (int i = 0; i < n / 2;i++) {
        int cur = a[i] - 'A';
        int nw = cur + sum;

        nw %= 26;
        a[i] = char('A' + nw);
    }
    sum = 0;
    for (auto& i : b) {
        sum += (i - 'A');
    }

    for (int i = 0; i < n / 2; i++) {
        int cur = b[i] - 'A';
        int nw = cur + sum;

        nw %= 26;
        b[i] = char('A' + nw);
    }

    for (int i = 0; i < n / 2; i++) {
        int cur = (a[i] - 'A') + (b[i] - 'A');
        cur %= 26;
        cout << char('A' + cur);
    }
    cout << "\n";
}