from sys import stdin
input = stdin.readline

INF = 1<<60

for _ in range(int(input())):
    N, M = map(int, input().split())
    AB = [list(map(int, input().split())) for _ in range(M)]

    l, r = -INF, INF
    SUM = 0
    for A, B in AB:
        l = max(l, A-B+1-SUM)
        r = min(r, A-SUM)
        SUM += B
    
    print("Yes" if l <= r else "No")