n = list(map(int, input().split()))
weekends = set(range(6, n[0] + 1, 7)) | set(range(7, n[0] + 1, 7))
meeting = set()
i = 0
while i < n[1]:
    a = list(map(int, input().split()))
    meeting = meeting | set(range(a[0], n[0] + 1, a[1])) - weekends
    i += 1
print(len(meeting))