def main():
    n, m = list(map(int, input().split()))
    Q = [list(map(int, input().split())) for _ in range(m)]
    if sum([b for a, b in Q]) != n:
        return 0
    a = Q[0][0]
    for i in range(m):
        Q[i][0] -= a
    l = 0
    r = n-1-Q[-1][0]
    a = 0
    for i in range(m):
        u, x = Q[i]
        a += x
        l0 = Q[i][0]+1
        if i < m-1: r0 = Q[i+1][0]
        else: r0 = n
        l = max(l, a-r0)
        r = min(r, a-l0)
    if l <= r:
        return 1
    return 0

for _ in range(int(input())):
    print("Yes" if main() else "No")