#[allow(unused_imports)]
use std::cmp::*;
#[allow(unused_imports)]
use std::collections::*;
use std::io::Read;

#[allow(dead_code)]
fn getline() -> String {
    let mut ret = String::new();
    std::io::stdin().read_line(&mut ret).ok().unwrap();
    ret
}

fn get_word() -> String {
    let stdin = std::io::stdin();
    let mut stdin=stdin.lock();
    let mut u8b: [u8; 1] = [0];
    loop {
        let mut buf: Vec<u8> = Vec::with_capacity(16);
        loop {
            let res = stdin.read(&mut u8b);
            if res.unwrap_or(0) == 0 || u8b[0] <= b' ' {
                break;
            } else {
                buf.push(u8b[0]);
            }
        }
        if buf.len() >= 1 {
            let ret = String::from_utf8(buf).unwrap();
            return ret;
        }
    }
}

#[allow(dead_code)]
fn get<T: std::str::FromStr>() -> T { get_word().parse().ok().unwrap() }

fn compile(a: &[char]) -> Vec<(char, u8)> {
    let mut ans: Vec<(char, u8)> = vec![];
    for &c in a {
        let l = ans.len();
        if c == '?' {
            ans[l - 1].1 = 1;
        } else if c == '?' {
            ans[l - 1].1 = 2;
        } else {
            ans.push((c, 0));
        }
    }
    ans
}

fn main() {
    let a: Vec<_> = getline().trim().chars().collect();
    let b: Vec<_> = getline().trim().chars().collect();
    let a = compile(&a);
    let b = compile(&b);
    let n = a.len();
    let m = b.len();
    const INF: i64 = 1 << 40;
    let mut dp = vec![vec![INF; m + 1]; n + 1];
    for i in 0..n + 1 {
        let (xc, xk) = a[i];
        for j in 0..m + 1 {
            let val = dp[i][j];
            let (yc, yk) = b[i];
            if xc == yc || (xk != 0 && yk != 0) {
                dp[i + 1][j + 1] = min(dp[i + 1][j + 1], val);
            } else {
                dp[i + 1][j + 1] = min(dp[i + 1][j + 1], val + 1);
            }
            let add = if yk != 0 || (xc == yc && xk == 2) {
                0
            } else {
                1
            };
            dp[i][j + 1] = min(dp[i][j + 1], val + add);
            let add = if xk != 0 || (xc == yc && yk == 2) {
                0
            } else {
                1
            };
            dp[i + 1][j] = min(dp[i + 1][j], val + add);
        }
    }
    println!("{}", dp[n][m]);
}