#include <iostream>
#include <vector>
#include <algorithm>
#include <stdio.h>

using namespace std;

long long int n;

long long int binarySearch(vector<long long int> &v, int num, int left, int right)
{
    int middle = (left + right)/2;
    if(v[middle] == num)
        return v[middle];
    else if(right-left <= 1) {
        if(v[left] >= num)
            return v[left];
        else if(v[right] >= num)
            return v[right];
        else
            return v[right+1];
    }
    else if(v[middle] < num) {
        return binarySearch(v, num, middle, right);
    }
    else {
        return binarySearch(v, num, left, middle);
    }
}

void update(vector<long long int> &t, int l, int r) //Modifica los datos en un rango [l,r]
{
    for (l += n, r += n+1; l < r; l >>= 1, r >>= 1)
    {
        if (l&1) t[l++]++;
        if (r&1) t[--r]++;
    }
}

long long int busqueda(vector<long long int> &v, long long int pos)
{
    long long int cant = v[1];
    pos += n;
    while(pos!=1)
    {
        cant += v[pos];
        pos>>=1;
    }
    return cant;
}

int main()
{
    vector<long long int> v2;
    for(long long int i = 1; i<=1000000000; i<<=1)
        v2.push_back(i);
    long long int interseccion = 0, searchl, searchr, m, t, l, r;
    scanf("%lld",&t);
    while(t--)
    {
        scanf("%lld %lld",&n,&m);
        vector<long long int> v(binarySearch(v2,n,0,v2.size())*2,0);
        while(m--)
        {
            scanf("%lld %lld",&l, &r);
            update(v,l+1,r-1);
            if(r-l>1)
            {
                searchl = busqueda(v,l);
                searchr = busqueda(v,r);
                interseccion += max(searchl,searchr)-min(searchl,searchr);
            }
        }
        printf("%lld\n",interseccion);
        interseccion = 0;
    }
    return 0;
}