n, m = map(int, input().split())
nums = [99] * n

for _ in range(m):
    n1, n2 = map(int, input().split())
    nums[n1-1] = min(nums[n1-1], n2)

# 0nara Hajiku
if nums[0] not in [99, 0]:
    print([x if x!=99 else 0 for x in nums])
else:
    print(-1)