// ---------- begin input macro ----------
// reference: https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8
macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
    ($($r:tt)*) => {
        let s = {
            use std::io::Read;
            let mut s = String::new();
            std::io::stdin().read_to_string(&mut s).unwrap();
            s
        };
        let mut iter = s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
}

macro_rules! input_inner {
    ($iter:expr) => {};
    ($iter:expr, ) => {};
    ($iter:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($iter, $t);
        input_inner!{$iter $($r)*}
    };
}

macro_rules! read_value {
    ($iter:expr, ( $($t:tt),* )) => {
        ( $(read_value!($iter, $t)),* )
    };
    ($iter:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
    };
    ($iter:expr, chars) => {
        read_value!($iter, String).chars().collect::<Vec<char>>()
    };
    ($iter:expr, bytes) => {
        read_value!($iter, String).bytes().collect::<Vec<u8>>()
    };
    ($iter:expr, usize1) => {
        read_value!($iter, usize) - 1
    };
    ($iter:expr, $t:ty) => {
        $iter.next().unwrap().parse::<$t>().expect("Parse error")
    };
}
// ---------- end input macro ----------

fn run() {
    input! {
        s: bytes,
    }
    let mut t = s.clone();
    let mut len = 0;
    while t.iter().any(|c| *c != b'?') {
        len += 1;
        let mut cnt = [0; 26];
        for t in t.iter() {
            if *t != b'?' {
                cnt[(*t - b'a') as usize] += 1;
            }
        }
        let mut pos = cnt.iter().rposition(|c| *c > 0).unwrap();
        for t in t.iter_mut() {
            if *t != b'?' {
                cnt[(*t - b'a') as usize] -= 1;
            }
            if *t == b'a' + pos as u8 {
                *t = b'?';
                pos = cnt.iter().rposition(|c| *c > 0).unwrap_or(0);
            }
        }
    }
    len = len.max(1);
    let mut s = s;
    let mut dp = vec![b'a'; len];
    for s in s.iter_mut().rev() {
        if *s == b'?' {
            *s = dp[len - 1];
        } else {
            let x = dp.iter().position(|c| *c <= *s).unwrap();
            dp[x] = *s;
        }
    }
    let s = s.into_iter().map(|c| c as char).collect::<String>();
    println!("{}", s);
}

fn main() {
    run();
}