from collections import deque
def bfs(v):
    q = deque()
    q.append(v)
    used = set()
    used.add(v)
    while q:
        v = q.popleft()
        if v not in used:
            q += data[v]
            used.add(v)

n, m = map(int, input().split())
data = {k: [] for k in range(n)}
for i in range(m):
    f, t = map(int, input().split())
    data[f] += t
q = deque()