use std::io::*;
use std::str::FromStr;
//use std::collections::VecDeque;
/*
const LOW_CASE_ALPHABET: [char; 26] = [
    'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's',
    't', 'u', 'v', 'w', 'x', 'y', 'z',
];
*/

fn main() {
    let t: usize = read();

    for _i in 0..t{
        let mut tmp = [0; 100001];
        let mut tmp_1 = 0;
        let mut tmp_2 = 0;
        let _n: usize = read();
        let m: usize = read();

        for _j in 0..m{
            let a: usize = read();
            let b: usize = read();
            tmp[a] = 1;
            tmp[b] = 1;
            if tmp_2 < max_u_2(a,b){
                tmp_2 = max_u_2(a,b);
            }
        }
        for _j in 0..=tmp_2{
            for _k in _i + 1..=tmp_2{
                if tmp[_j] == tmp[_k]{
                    tmp_1 = 1;
                }
            }
        }
        if tmp_1 == 1{
            println!("Yes");
        }else{
            println!("No");
        }
    }

}

    /*
    let n: usize = read();
    let q: usize = read();
    let mut connect: Vec<Vec<usize>> = vec![Vec::new();n + 1];
    let mut queue = VecDeque::new();

    for _ in 0..n - 1{
        let a: usize = read();
        let b: usize = read();
        connect[a].push(b);
        connect[b].push(a);
    }
    let mut counter = vec![0; n + 1];
    for _ in 0..q{
        let p: usize = read();
        let x: usize = read();
        counter[p] += x;
    }
    queue.push_back(1);
    let mut visited = vec![false; n + 1];
    visited[1] = true;
    while queue.len() > 0{
        let now: usize = match queue.pop_back() {
            Some(value) => value,
            None => {
                0
            },
        };


        let now_number = counter[now];
        for to in &connect[now]{
            if visited[*to] == false{
                counter[*to] += now_number;
                visited[*to] = true;
                queue.push_back(*to);
            }
        }
    }
    
    for _i in 1..=n{
        print!("{}",counter[_i]);
        if _i != n + 1{
            print!(" ");
        }
    }*/
/*
pub fn mod_pow(mut base: u64, mut exp: u64, modulus: u64) -> u64{
    let mut result = 1;
    while exp > 0{
        if exp % 2 == 1{
            result = result * base % modulus;
        }
        base = base * base % modulus;
        exp >>= 1;
    }
    result
}
*/

/*
pub fn perfect(value_1: usize) -> usize {
    let mut perfect_number = Vec::new();
    let mut tmp_1 = 0;
    for _i in 2..=value_1 {
        let mut tmp = 0;
        for _j in 1..=((_i as f64).powf(0.5)) as usize {
            if _i % _j == 0 {
                if _j * _j == _i {
                    tmp += _j;
                } else {
                    tmp += _j + (_i / _j);
                }
            }
        }
        tmp -= _i;

        if tmp == _i {
            perfect_number.push(_i);
        }
    }

    for _i in &perfect_number{
        if tmp_1 == perfect_number.len() - 1{
            break;
        }
        println!("{}", _i);
        tmp_1 += 1;
    }

    perfect_number[perfect_number.len() - 1]
}
*/

/*
pub fn prime_number(value_1: usize, value_2: usize) -> usize {
    let mut primary = Vec::new();
    primary.push(2);

    for _i in 2..=value_1 {
        let mut flag = 0;
        for _j in &primary {
            if _i % _j == 0 {
                flag = 1;
                break;
            }
        }
        if flag == 0 {
            primary.push(_i);
        }
        if primary.len() == value_2 {
            return primary[primary.len() - 1];
        }
    }

    0
}
*/

/*
pub fn ctoi(c: char) -> isize {
    c as isize - '0' as isize
}

pub fn stoi(c: String) -> isize {
    c.parse::<isize>().unwrap()
}
*/
/*
pub fn find_char(sentence: Vec<char>, target: char, start: isize) -> isize {
    for _i in start as usize..sentence.len() {
        if sentence[_i] == target {
            return _i as isize;
        }
    }
    -1
}
*/

/*
pub fn hex_to_binary_2(hex_string: String, x: u32) -> Option<String> {
    match i64::from_str_radix(&hex_string, x) {
        Ok(decimal) => Some(format!("{}", decimal)),
        Err(_) => None,
    }
}
*/

/*
pub fn hex_to_binary(hex_string: &str, x: u32) -> Option<String> {
    match i64::from_str_radix(hex_string, x) {
        Ok(decimal) => Some(format!("{}", decimal)),
        Err(_) => None,
    }
}
*/

/*
pub fn my_floor(x: f64) -> f64 {
    (x * 1000.0).floor() / 1000.0
}
*/

/*
pub fn upper_lower(x: char) -> char {
    let result: char;

    if x.is_uppercase() {
        result = x.to_ascii_lowercase();
    } else if x.is_lowercase() {
        result = x.to_ascii_uppercase();
    } else {
        result = x;
    }

    result
}
*/

/*
pub fn maxf_2(x: f64, y: f64) -> f64 {
    if x >= y {
        x
    } else {
        y
    }
}
*/

/*
pub fn max_2(x: isize, y: isize) -> isize {
    if x >= y {
        x
    } else {
        y
    }
}
*/


pub fn max_u_2(x: usize, y: usize) -> usize {
    if x >= y {
        x
    } else {
        y
    }
}


/*
pub fn min_2(x: isize, y: isize) -> isize {
    if x >= y {
        y
    } else {
        x
    }
}
*/

/*
pub fn min_u_2(x: usize, y: usize) -> usize {
    if x >= y {
        y
    } else {
        x
    }
}
*/

/*
pub fn max_3(x: isize, y: isize, z: isize) -> isize {
    if (x >= y && y >= z) || (x >= z && z >= y){
        x
    } else if (y >= x && x >= z) || (y >= z && z >= x) {
        y
    } else {
        z
    }
}
*/

/*
pub fn max_u_3(x: usize, y: usize, z: usize) -> usize {
    if (x >= y && y >= z) || (x >= z && z >= y){
        x
    } else if (y >= x && x >= z) || (y >= z && z >= x) {
        y
    } else {
        z
    }
}
*/

/*
pub fn min_3(x: isize, y: isize, z: isize) -> isize {
    if (x <= y && y <= z) || (x <= z && z <= y){
        x
    } else if (y <= x && x <= z) || (y <= z && z <= x) {
        y
    } else {
        z
    }
}
*/

/*
pub fn min_u_3(x: usize, y: usize, z: usize) -> usize {
    if (x <= y && y <= z) || (x <= z && z <= y){
        x
    } else if (y <= x && x <= z) || (y <= z && z <= x) {
        y
    } else {
        z
    }
}
*/

pub fn read_text() -> String {
    let mut word = String::new();
    std::io::stdin().read_line(&mut word).ok();
    let answer = word.trim().to_string();

    answer
}

pub fn read_array() -> Vec<char> {
    let array: String = read();
    let chars: Vec<char> = array.trim().chars().collect::<Vec<char>>();
    chars
}

pub fn read<T: FromStr>() -> T {
    let stdin = stdin();
    let stdin = stdin.lock();
    let token: String = stdin
        .bytes()
        .map(|c| c.expect("failed to read char") as char)
        .skip_while(|c| c.is_whitespace())
        .take_while(|c| !c.is_whitespace())
        .collect();
    token.parse().ok().expect("failed to parse token")
}

pub fn read_line<T: FromStr>() -> String {
    let stdin = stdin();
    let stdin = stdin.lock();
    stdin
        .lines()
        .next()
        .expect("No line in the input")
        .expect("Failed to read line")
}