#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include<iostream>
#include<cstdint>
#include<cstddef>
using namespace std;
using i32 = int_fast32_t;
using i64 = int_fast64_t;
using usize = size_t;
#define rep(i, n) for (usize i = 0; i < (usize)(n); i++)
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()
using P = pair<i64,i64>;

int main(){
ios::sync_with_stdio(false);
std::cin.tie(nullptr);
string s;
cin >> s;
string t = "abcdefghijklmnopqrstuvwxyz";
string ans = "to";
rep(i,s.size()){
    if(s[i] != t[i]){
        ans = t[i] + ans + s[i];
    }
}
cout << ans << endl;
}