// Khajiit
// Solution by Jacob Plachta

#define DEBUG 0

#include <algorithm>
#include <functional>
#include <numeric>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <complex>
#include <cstdlib>
#include <ctime>
#include <cstring>
#include <cassert>
#include <string>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <unordered_map>
#include <unordered_set>
#include <deque>
#include <queue>
#include <stack>
#include <bitset>
#include <sstream>
using namespace std;

#define LL long long
#define LD long double
#define PR pair<int,int>

#define Fox(i,n) for (i=0; i<n; i++)
#define Fox1(i,n) for (i=1; i<=n; i++)
#define FoxI(i,a,b) for (i=a; i<=b; i++)
#define FoxR(i,n) for (i=(n)-1; i>=0; i--)
#define FoxR1(i,n) for (i=n; i>0; i--)
#define FoxRI(i,a,b) for (i=b; i>=a; i--)
#define Foxen(i,s) for (i=s.begin(); i!=s.end(); i++)
#define Min(a,b) a=min(a,b)
#define Max(a,b) a=max(a,b)
#define Sz(s) int((s).size())
#define All(s) (s).begin(),(s).end()
#define Fill(s,v) memset(s,v,sizeof(s))
#define pb push_back
#define mp make_pair
#define x first
#define y second

template<typename T> T Abs(T x) { return(x < 0 ? -x : x); }
template<typename T> T Sqr(T x) { return(x * x); }
string plural(string s) { return(Sz(s) && s[Sz(s) - 1] == 'x' ? s + "en" : s + "s"); }

const int INF = (int)1e9;
const LD EPS = 1e-12;
const LD PI = acos(-1.0);

#if DEBUG
#define GETCHAR getchar
#else
#define GETCHAR getchar_unlocked
#endif

bool Read(int& x) {
	char c, r = 0, n = 0;
	x = 0;
	for (;;) {
		c = GETCHAR();
		if ((c < 0) && (!r))
			return(0);
		if ((c == '-') && (!r))
			n = 1;
		else if ((c >= '0') && (c <= '9'))
			x = x * 10 + c - '0', r = 1;
		else if (r)
			break;
	}
	if (n)
		x = -x;
	return(1);
}

bool ReadLL(LL& x) {
	char c, r = 0, n = 0;
	x = 0;
	for (;;) {
		c = GETCHAR();
		if ((c < 0) && (!r))
			return(0);
		if ((c == '-') && (!r))
			n = 1;
		else if ((c >= '0') && (c <= '9'))
			x = x * 10 + c - '0', r = 1;
		else if (r)
			break;
	}
	if (n)
		x = -x;
	return(1);
}

#define MOD 1000000007
#define LIM 1000005

int N, M;
char X[LIM], Y[LIM];

LL Solve(int s) {
	int i;
	LL sum = 0;
	int hasA = 0, needsA = 0;
	FoxR(i, M) {
		if (X[s + i] == 'A')
			hasA++;
		if (Y[s + i] == 'A')
			needsA++;
		sum += Abs(hasA - needsA);
	}
	return(sum);
}

int main() {
	if (DEBUG)
		freopen("in.txt", "r", stdin);
	// vars
	int T, t;
	int i;
	// testcase loop
	Read(T);
	Fox1(t, T) {
		// input
		Read(N), Read(M);
		scanf("%s%s", &X, &Y);
		// handle each spoke
		LL ans = 0;
		Fox(i, N)
			ans += Solve(i * M + 1);
		// output
		printf("Case #%d: %lld\n", t, ans);
	}
	return(0);
}