#include<algorithm>
#include<iostream>
#include<vector>
#include<map>
#include<cassert>
#include<set>
#include<queue>
using namespace std;
using ll = long long;

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    string s;
    cin>>s;
    vector<int> cnt(26,0);
    vector<int> use;
    for(int i = s.size()-1;i>=0;i--){
        if(s[i]!='?'){
            int ni = s[i] - 'a';
            int nk = -1;
            for(int j = ni;j>=0;j--){
                if(cnt[j]){
                    nk = j;
                    break;
                }
            }
            if(nk!=-1){
                cnt[nk] = 0;
                cnt[ni] = 1;
            }else{
                for(auto j:use) s[j] = 'a';
                use.clear();
                cnt[ni] = 1;
            }
        }else{
            int ni = -1;
            for(int j = 0;j<26;j++){
                if(cnt[j]){
                    ni = j;
                    break;
                }
            }
            if(ni!=-1){
                s[i] = 'a' + ni;
                use.push_back(i);
            }else{
                s[i] = 'a';
                cnt[0] = 1;
            }
        }
    }
    cout<<s<<endl;
}