import sys input = sys.stdin.readline from collections import deque def topsort(G): Q = deque() N = len(G) count = [0] * N for u in range(N): for v, _, _ in G[u]: count[v] += 1 for u in range(N): if count[u] == 0: Q.append(u) anslst = [] while Q: u = Q.pop() anslst.append(u) for v, _, _ in G[u]: count[v] -= 1 if count[v] == 0: Q.append(v) return anslst def bfs(G, s): Q = deque([s]) N = len(G) dist = [-1] * N par = [-1] * N dist[s] = 0 while Q: u = Q.popleft() for v in G[u]: if dist[v] != -1: continue dist[v] = dist[u] + 1 par[v] = u Q.append(v) return dist N, M = map(int, input().split()) G = [[] for i in range(N + 1)] G1 = [[] for i in range(N + 1)] G2 = [[] for i in range(N + 1)] D = [] for i in range(M): u, v, l, a = list(map(int, input().split())) D.append([u, v, l, a]) G1[u].append(v) G2[v].append(u) dist1 = bfs(G1, 0) dist2 = bfs(G2, N) for u, v, l, a in D: if dist1[u] == -1 or dist1[v] == -1 or dist2[u] == -1 or dist2[v] == -1: continue G[u].append((v, l, a)) dp = [0] * (N + 1) dp_sum = [0] * (N + 1) dp[0] = 1 L = topsort(G) if len(L) != N + 1: print("INF") exit() mod = 10**9 + 7 for u in L: for v, l, a in G[u]: dp[v] += dp[u] * a dp[v] %= mod dp_sum[v] += (dp_sum[u] + dp[u] * l) * a dp_sum[v] %= mod print(dp_sum[-1])