import java.io.*;

class Main {
    public static void main(String[] args) throws IOException {
        InputStreamReader isr = new InputStreamReader(System.in);
        BufferedReader in = new BufferedReader(isr);
        int n = Integer.parseInt(in.readLine().trim());
        char[] a = in.readLine().toCharArray();
        int m = Integer.parseInt(in.readLine().trim());
        char[] b = in.readLine().toCharArray();

        in.close();
        isr.close();

        OutputStreamWriter osw = new OutputStreamWriter(System.out);
        BufferedWriter out = new BufferedWriter(osw);

        int[][] f = new int[n+1][m+1];

        //关键：初始化f，从零到长度为i的序列需要操作i次；从长度为i变为长度为0也需操作i次
        for (int i = 1; i <= n; i++) f[i][0] = i;
        for (int j = 1; j <= m; j++) f[0][j] = j;

        for (int i = 1; i <= n; i++)
            for (int j = 1; j <= m; j++) {
                f[i][j] = Math.min(f[i-1][j], f[i][j-1]) + 1;
                if (a[i - 1] != b[j - 1]) f[i][j] = Math.min(f[i][j], f[i-1][j-1]+1);
                //易错点：遗漏不操作的情况
                else f[i][j] = Math.min(f[i][j], f[i-1][j-1]);
            }

        out.write(f[n][m]+"");
        out.flush();
        out.close();
        osw.close();
    }
}