#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("inline")
#include<bits/stdc++.h>
using namespace std;
inline int my_getchar_unlocked(){
  static char buf[1048576];
  static int s = 1048576;
  static int e = 1048576;
  if(s == e && e == 1048576){
    e = fread_unlocked(buf, 1, 1048576, stdin);
    s = 0;
  }
  if(s == e){
    return EOF;
  }
  return buf[s++];
}
inline void rd(char &c){
  int i;
  for(;;){
    i = my_getchar_unlocked();
    if(i!=' '&&i!='\n'&&i!='\r'&&i!='\t'&&i!=EOF){
      break;
    }
  }
  c = i;
}
inline int rd(char c[]){
  int i;
  int sz = 0;
  for(;;){
    i = my_getchar_unlocked();
    if(i!=' '&&i!='\n'&&i!='\r'&&i!='\t'&&i!=EOF){
      break;
    }
  }
  c[sz++] = i;
  for(;;){
    i = my_getchar_unlocked();
    if(i==' '||i=='\n'||i=='\r'||i=='\t'||i==EOF){
      break;
    }
    c[sz++] = i;
  }
  c[sz]='\0';
  return sz;
}
struct MY_WRITER{
  char buf[1048576];
  int s;
  int e;
  MY_WRITER(){
    s = 0;
    e = 1048576;
  }
  ~MY_WRITER(){
    if(s){
      fwrite_unlocked(buf, 1, s, stdout);
    }
  }
}
;
MY_WRITER MY_WRITER_VAR;
void my_putchar_unlocked(int a){
  if(MY_WRITER_VAR.s == MY_WRITER_VAR.e){
    fwrite_unlocked(MY_WRITER_VAR.buf, 1, MY_WRITER_VAR.s, stdout);
    MY_WRITER_VAR.s = 0;
  }
  MY_WRITER_VAR.buf[MY_WRITER_VAR.s++] = a;
}
inline void wt_L(char a){
  my_putchar_unlocked(a);
}
inline void wt_L(const char c[]){
  int i=0;
  for(i=0;c[i]!='\0';i++){
    my_putchar_unlocked(c[i]);
  }
}
template<class T, class S> int arrCountVal(int N, T A[], S val){
  int i;
  int res = 0;
  for(i=(0);i<(N);i++){
    if(A[i]==val){
      res++;
    }
  }
  return res;
}
template<class S> int arrCountVal(string A, S val){
  int i;
  int res = 0;
  for(i=(0);i<(A.size());i++){
    if(A[i]==val){
      res++;
    }
  }
  return res;
}
int N;
int sz;
int cur;
char S[100000+2];
char nx[100000+2];
char res[100000+2];
int ind[256];
int main(){
  int i;
  N = rd(S);
  for(i=(0);i<(N);i++){
    res[i] = S[i];
  }
  for(;;){
    for(i=('a');i<('z'+1);i++){
      ind[i] = -1;
    }
    for(i=(0);i<(N);i++){
      ind[S[i]] = i;
    }
    sz = 0;
    cur = 'z';
    for(i=(0);i<(N);i++){
      while(cur > 'a' && ind[cur] < i){
        cur--;
      }
      if(S[i] == cur){
        continue;
      }
      nx[sz++] = S[i];
    }
    if(arrCountVal(sz,nx,'?') < sz){
      N = sz;
      for(i=(0);i<(N);i++){
        S[i] = nx[i];
      }
      continue;
    }
    sz = 0;
    cur = 'z';
    for(i=(0);i<(N);i++){
      while(cur > 'a' && ind[cur] < i){
        cur--;
      }
      if(S[i] == '?'){
        while(res[sz] != '?'){
          sz++;
        }
        res[sz] = cur;
      }
    }
    break;
  }
  wt_L(res);
  wt_L('\n');
  return 0;
}
// cLay version 20210708-1

// --- original code ---
// int N, sz, cur;
// char S[1d5+2], nx[];
// char res[];
// int ind[256];
// {
//   rd(S@N);
//   rep(i,N) res[i] = S[i];
//   for(;;){
//     // S[N] = '\0'; puts(S);
//     rep(i,'a','z'+1) ind[i] = -1;
//     rep(i,N) ind[S[i]] = i;
//     sz = 0; cur = 'z';
//     rep(i,N){
//       while(cur > 'a' && ind[cur] < i) cur--;
//       if(S[i] == cur) continue;
//       nx[sz++] = S[i];
//     }
//     if(arrCountVal(sz,nx,'?') < sz){
//       N = sz;
//       rep(i,N) S[i] = nx[i];
//       continue;
//     }
//     sz = 0; cur = 'z';
//     rep(i,N){
//       while(cur > 'a' && ind[cur] < i) cur--;
//       if(S[i] == '?'){
//         while(res[sz] != '?') sz++;
//         res[sz] = cur;
//       }
//     }
//     break;
//   }
//   wt(res);
// }