#include <bits/stdc++.h>

using i32 = std::int32_t;
using u32 = std::uint32_t;
using i64 = std::int64_t;
using u64 = std::uint64_t;
using i128 = __int128_t;
using u128 = __uint128_t;
using isize = std::ptrdiff_t;
using usize = std::size_t;

class rep {
    struct Iter {
        usize itr;
        constexpr Iter(const usize pos) noexcept : itr(pos) {}
        constexpr void operator++() noexcept { ++itr; }
        constexpr bool operator!=(const Iter& other) const noexcept { return itr != other.itr; }
        constexpr usize operator*() const noexcept { return itr; }
    };
    const Iter first, last;

  public:
    explicit constexpr rep(const usize first, const usize last) noexcept : first(first), last(std::max(first, last)) {}
    constexpr Iter begin() const noexcept { return first; }
    constexpr Iter end() const noexcept { return last; }
};

class revrep {
    struct Iter {
        usize itr;
        constexpr Iter(const usize pos) noexcept : itr(pos) {}
        constexpr void operator++() noexcept { --itr; }
        constexpr bool operator!=(const Iter& other) const noexcept { return itr != other.itr; }
        constexpr usize operator*() const noexcept { return itr; }
    };
    const Iter first, last;

  public:
    explicit constexpr revrep(const usize first, const usize last) noexcept
        : first(last - 1), last(std::min(first, last) - 1) {}
    constexpr Iter begin() const noexcept { return first; }
    constexpr Iter end() const noexcept { return last; }
};

template <class T> bool setmax(T& lhs, const T& rhs) {
    if (lhs < rhs) {
        lhs = rhs;
        return true;
    }
    return false;
}

template <class T> using Vec = std::vector<T>;

void main_() {
    std::string S;
    std::cin >> S;
    const auto N = S.size();
    if (S == std::string(N, '?')) {
        std::cout << std::string(N, 'a') << '\n';
        return;
    }
    Vec<int> A(N);
    for (const auto i : rep(0, N)) {
        A[i] = (S[i] == '?' ? -1 : S[i] - 'a');
    }
    Vec<std::array<int, 27>> dp(N + 1);
    for (auto& arr : dp) {
        arr.fill(-1);
    }
    dp[N][0] = 26;
    for (const auto i : revrep(0, N)) {
        dp[i] = dp[i + 1];
        if (A[i] != -1) {
            for (const auto j : rep(0, 26)) {
                if (A[i] < dp[i + 1][j]) {
                    setmax(dp[i][j + 1], A[i]);
                }
            }
        }
    }
    usize lis = 0;
    while (lis < 26 and dp[0][lis + 1] != -1) {
        lis += 1;
    }
    std::array<int, 27> left;
    left.fill(26);
    left[0] = -1;
    for (const auto i : rep(0, N)) {
        if (A[i] == -1) {
            usize l = 0, r = 26;
            for (const auto j : rep(0, 26)) {
                while (l < 26 and left[l + 1] < (int)j) {
                    l += 1;
                }
                while ((int)j >= dp[i + 1][r]) {
                    r -= 1;
                }
                if (l + 1 + r <= lis) {
                    *std::lower_bound(left.begin(), left.end(), A[i]) = j;
                    std::cout << (char)(j + 'a');
                    break;
                }
            }
        } else {
            *std::lower_bound(left.begin(), left.end(), A[i]) = A[i];
            std::cout << (char)(A[i] + 'a');
        }
    }
    std::cout << '\n';
}

int main() {
    std::ios_base::sync_with_stdio(false);
    std::cin.tie(nullptr);
    main_();
    return 0;
}