#include <bits/stdc++.h>
using namespace std;
#define ls u << 1
#define rs u << 1 | 1
#define LL long long
#define int long long
#define PII pair <int, int>
#define fi first
#define se second
#define pub push_back
#define pob pop_back
#define puf push_front
#define pof pop_front
#define lb lower_bound
#define ub upper_bound
#define i128 __int128
#define pcnt(x) __builtin_popcount(x)
#define mem(a,goal) memset(a, (goal), sizeof(a))
#define rep(x,start,end) for(int x = (start) - ((start) > (end)); x != (end) - ((start) > (end)); ((start) < (end) ? x ++ : x --))
#define aLL(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
const int INF = 998244353;
const int P = 1e9 + 7;
const int N = 2e5 + 5;
int s1[N + 1][30], s2[N + 1][30];
void solve()
{
    int n, q;
    cin >> n >> q;
    vector<char> a(n + 1), b(n + 1);
    for(int i = 1; i <= n; ++ i) cin >> a[i];
    for(int i = 1; i <= n; ++ i) cin >> b[i];
    for(int i = 1; i <= n; ++ i)
    {
        s1[i][a[i] - 'a'] ++;
        for(int j = 0; j < 26; ++ j)
        {
            s1[i][j] += s1[i - 1][j];
        }
    }
    
    for(int i = 1; i <= n; ++ i)
    {
        s2[i][b[i] - 'a'] ++;
        for(int j = 0; j < 26; ++ j)
        {
            s2[i][j] += s2[i - 1][j];
        }
    }
 
    while(q --)
    {
        int l, r;
        cin >> l >> r;
        int sum = 0;
 
        for(int i = 0; i < 26; ++ i)
        {
            int p = s1[r][i] - s1[l - 1][i];
            int q = s2[r][i] - s2[l - 1][i];
            sum += abs (p - q);
        }
        cout << sum / 2 << '\n';
    }
}
signed main()
{
    int t;
    cin >> t;
    while(t --) solve();
    return 0;
}