Lockpicking Chef

#include <bits/stdc++.h>

using namespace std;

#define ll     long long
#define _test   int _TEST; cin>>_TEST; while(_TEST--)

int main()
{
    _test
    {
        int n, m;
        cin>>n>>m;

        string a, b;
        cin>>a>>b;

        int ans = 1e9;

        for(int i=0; i+m<=n; i++)
        {
            int x = 0;

            for(int j=0; j<m; j++)
                x += min({abs(a[i+j]-b[j]), '9'+1-b[j]+a[i+j]-'0', '9'+1+b[j]-a[i+j]-'0'});

            ans = min(ans, x);
        }

        cout<<ans<<"\n";
    }
}