#include <bits/stdc++.h>
#include <atcoder/modint>
using namespace std;
using mint = atcoder::modint998244353;

int main() {
    string s;
    cin >> s;
    int n = (int)s.size();
    
    vector dp(n + 1, vector<mint>(4, 0));
    dp[0][0] = 1;
    for(int i = 0; i < n; i++) {
        // i+1文字目を追加する時
        if(s[i] == '0' || s[i] == '?') {
            dp[i+1][1] += dp[i][0];
            dp[i+1][3] += dp[i][2];
        }
        if(s[i] == '1' || s[i] == '?') {
            dp[i+1][2] += dp[i][1];
        }
        // i+1文字目を追加しない時
        for(int j = 0; j < 4; j++) {
            dp[i+1][j] += dp[i][j] * (s[i] == '?' ? 2 : 1);
        }
    }
    mint ans = dp[n][3];
    cout << ans.val() << endl;
}