题目的意思是必修同时俩，所以删掉k操作就行

#include<cstring>
#include<iostream>

using namespace std;

string start, en;
int dx[] = {-1, 0}, l; 

void turn(int x) {
    for(int i = 0; i < 2; i ++) {
        int a = x + dx[i];
        if(a >= 0 && a < l) 
            start[a] = (start[a] == '*') ? 'o' : '*';
    }
}

int work() {
    int ans = 1e6;
    string backup = start;
    int res = 0;

    for(int i = 0; i < l; i ++) {
        if(start[i] != en[i]) {
            turn(i + 1);
            res ++;
        }
    }

    start = backup;
    if(start[l - 1] == en[l - 1]) ans = min(ans, res);

    return ans;
}

int main() {
    cin >> start >> en;
    l = start.length();
    cout << work() << endl;
    return 0;
}