#include<bits/stdc++.h>
using namespace std;
#define int long long
int dp[1005][1005],prei[1005][1005],prej[1005][1005],ok[1005][1005];
char s[1005],t[1005],res[1005];int n,m;int pi[1005];
signed main(){
	scanf("%s",s+1);n = strlen(s+1);
	scanf("%s",t+1);m = strlen(t+1);
	pi[1] = 0;int j = 0;
	for(int i= 2;i<=n;i++){
		while(j and t[j+1]!=t[i])j = pi[j];
		if(t[j+1] == t[i])j++;pi[i] = j;
	}for(int i=0;i<=n;i++)memset(dp,128,sizeof(dp));
	dp[0][0] = 0;
	for(int i= 1;i<=n;i++){
		for(int j =1;j<=m;j++){
			
			if(s[i] == t[j] or s[i] == '?'){
				if(dp[i-1][j-1]>dp[i][j]){
					prei[i][j] = i-1,prej[i][j] = j-1;ok[i][j] = 1;dp[i][j] = dp[i-1][j-1];
				}
			}
		}dp[i][m]++;
		dp[i][0] = dp[i-1][0];prei[i][0] = i-1,prej[i][0] = 0,ok[i][0] = 0;
		for(int j =1;j<=m;j++){
			if(dp[i][j]>dp[i][0]){
				prei[i][0]= i,prej[i][0] = j,ok[i][0] = 0;dp[i][0] = dp[i][j];
			}
		}
		for(int j = pi[m];j;j = pi[j]){
			if(dp[i][m]>dp[i][j]){
				dp[i][j] = dp[i][m];
				prei[i][j] = i,prej[i][j] = m,ok[i][j] = 0;
			}
		}//for(int j =0;j<=m;j++)cout << dp[i][j] << " ";cout << endl;
	}int mxpos =0;for(int i = 0;i<=m;i++)if(dp[n][i]>dp[n][mxpos])mxpos =i ;
//	cout << dp[n][m] << endl;
	int i = n;j = mxpos;
	for(int i= 1;i<=n;i++)res[i] = s[i];
	while(i!=0 or j!=0){
//		cout << " " << i << " " << j << " " << ok[i][j] << endl;
		if(ok[i][j])res[i] = t[j];
		int ii = i,jj = j;i = prei[ii][jj],j =prej[ii][jj];
	}cout << dp[n][mxpos] << endl;
	for(int i= 1;i<=n;i++)if(res[i] == '?')res[i] = 'a';
	for(int i =1;i<=n;i++)cout << res[i];
	return 0;
}/*
winlose???winl???w??
win
*/