n,m = map(int,input().split())
n += 1
g = [[] for _ in range(n)]
edges = []
for _ in range(m):
    u,v,l,a = map(int,input().split())
    g[u].append((v,l,a))
    edges.append((u,v))

ok = [0]*n
ok[0] = 1
q = [0]
while q:
    u = q.pop()
    for v,l,a in g[u]:
        if ok[v]==0:
            ok[v] = 1
            q.append(v)


ind = [0]*n
for u,v in edges:
    if ok[u]:
        ind[v] += 1

MOD = 10**9+7
q = [i for i in range(n) if ok[i] and ind[i]==0]
dpnum = [0]*n
dpval = [0]*n
dpnum[0] = 1
while q:
    u = q.pop()
    for v,l,a in g[u]:
        dpnum[v] += a*dpnum[u]
        dpnum[v] %= MOD
        dpval[v] += (dpval[u] + dpnum[u]*l)%MOD*a
        dpval[v] %= MOD
        ind[v] -= 1
        if ind[v]==0: q.append(v)

if sum(ind):
    print("INF")
else:
    print(dpval[-1])