from collections import defaultdict, deque, Counter

from heapq import heappush, heappop, heapify

import math

import bisect

import random

from itertools import permutations, accumulate, combinations, product

import sys

from copy import deepcopy

import string

from bisect import bisect_left, bisect_right

from math import factorial, ceil, floor

from operator import mul

from functools import reduce





sys.setrecursionlimit(2147483647)

INF = 10 ** 20

def LI(): return list(map(int, sys.stdin.buffer.readline().split()))

def I(): return int(sys.stdin.buffer.readline())

def LS(): return sys.stdin.buffer.readline().rstrip().decode('utf-8').split()

def S(): return sys.stdin.buffer.readline().rstrip().decode('utf-8')

def IR(n): return [I() for i in range(n)]

def LIR(n): return [LI() for i in range(n)]

def SR(n): return [S() for i in range(n)]

def LSR(n): return [LS() for i in range(n)]

def SRL(n): return [list(S()) for i in range(n)]

mod = 1000000007







n, m = LI()

G = [[] for _ in range(n)]

for a, b, c in LIR(m):

    G[a - 1] += [(b - 1, c)]



# 負の閉路がなかったら高々n-1回で更新は終わるはずn回目に更新が起こったとしたら負の閉路がある。

def bellman_ford(G, s=0):

    n = len(G)

    dist = [-INF] * n

    dist[s] = 0

    v_nows = {s}

    for _ in range(n):

        v_changeds = set()

        for u in v_nows:

            for v, c in G[u]:

                if dist[u] + c > dist[v]:

                    dist[v] = dist[u] + c

                    v_changeds.add(v)

        v_nows = v_changeds

    if not v_changeds:

        return dist[n - 1]

    if n - 1 in v_nows:

        return 'inf'

    for i in v_nows:

        dist[i] = INF

    dq = deque(v_nows)

    while dq:

        u = dq.popleft()

        for v, c in G[u]:

            if v == n - 1:

                return 'inf'

            if dist[v] != INF:

                dist[v] = INF

                dq += [v]

    return dist[n - 1]







print((bellman_ford(G)))



from collections import defaultdict, deque, Counter

from heapq import heappush, heappop, heapify

import math

import bisect

import random

from itertools import permutations, accumulate, combinations, product

import sys

from copy import deepcopy

import string

from bisect import bisect_left, bisect_right

from math import factorial, ceil, floor

from operator import mul

from functools import reduce





sys.setrecursionlimit(2147483647)

INF = 10 ** 20

def LI(): return list(map(int, sys.stdin.buffer.readline().split()))

def I(): return int(sys.stdin.buffer.readline())

def LS(): return sys.stdin.buffer.readline().rstrip().decode('utf-8').split()

def S(): return sys.stdin.buffer.readline().rstrip().decode('utf-8')

def IR(n): return [I() for i in range(n)]

def LIR(n): return [LI() for i in range(n)]

def SR(n): return [S() for i in range(n)]

def LSR(n): return [LS() for i in range(n)]

def SRL(n): return [list(S()) for i in range(n)]

mod = 1000000007







n, m = LI()

G = [[] for _ in range(n)]

for a, b, c in LIR(m):

    G[a - 1] += [(b - 1, c)]



# 負の閉路がなかったら高々n-1回で更新は終わるはずn回目に更新が起こったとしたら負の閉路がある。

def bellman_ford(G, s=0):

    n = len(G)

    dist = [-INF] * n

    dist[s] = 0

    v_nows = {s}

    for _ in range(n):

        v_changeds = set()

        for u in v_nows:

            for v, c in G[u]:

                if dist[u] + c > dist[v]:

                    dist[v] = dist[u] + c

                    v_changeds.add(v)

        v_nows = v_changeds

    if not v_changeds:

        return dist[n - 1]

    for i in v_nows:

        dist[i] = INF

    dq = deque(v_nows)

    while dq:

        u = dq.popleft()

        if u == n - 1:

            return "inf"

        for v, c in G[u]:

            if v == n - 1:

                return 'inf'

            if dist[v] != INF:

                dist[v] = INF

                dq += [v]

    return dist[n - 1]







print((bellman_ford(G)))



from collections import defaultdict, deque, Counter
from heapq import heappush, heappop, heapify
import math
import bisect
import random
from itertools import permutations, accumulate, combinations, product
import sys
from copy import deepcopy
import string
from bisect import bisect_left, bisect_right
from math import factorial, ceil, floor
from operator import mul
from functools import reduce

sys.setrecursionlimit(2147483647)
INF = 10**20


def LI():
    return list(map(int, sys.stdin.buffer.readline().split()))


def I():
    return int(sys.stdin.buffer.readline())


def LS():
    return sys.stdin.buffer.readline().rstrip().decode("utf-8").split()


def S():
    return sys.stdin.buffer.readline().rstrip().decode("utf-8")


def IR(n):
    return [I() for i in range(n)]


def LIR(n):
    return [LI() for i in range(n)]


def SR(n):
    return [S() for i in range(n)]


def LSR(n):
    return [LS() for i in range(n)]


def SRL(n):
    return [list(S()) for i in range(n)]


mod = 1000000007
n, m = LI()
G = [[] for _ in range(n)]
for a, b, c in LIR(m):
    G[a - 1] += [(b - 1, c)]
# 負の閉路がなかったら高々n-1回で更新は終わるはずn回目に更新が起こったとしたら負の閉路がある。
def bellman_ford(G, s=0):
    n = len(G)
    dist = [-INF] * n
    dist[s] = 0
    v_nows = {s}
    for _ in range(n):
        v_changeds = set()
        for u in v_nows:
            for v, c in G[u]:
                if dist[u] + c > dist[v]:
                    dist[v] = dist[u] + c
                    v_changeds.add(v)
        v_nows = v_changeds
    if not v_changeds:
        return dist[n - 1]
    if n - 1 in v_nows:
        return "inf"
    for i in v_nows:
        dist[i] = INF
    dq = deque(v_nows)
    while dq:
        u = dq.popleft()
        for v, c in G[u]:
            if v == n - 1:
                return "inf"
            if dist[v] != INF:
                dist[v] = INF
                dq += [v]
    return dist[n - 1]


print((bellman_ford(G)))

from collections import defaultdict, deque, Counter
from heapq import heappush, heappop, heapify
import math
import bisect
import random
from itertools import permutations, accumulate, combinations, product
import sys
from copy import deepcopy
import string
from bisect import bisect_left, bisect_right
from math import factorial, ceil, floor
from operator import mul
from functools import reduce

sys.setrecursionlimit(2147483647)
INF = 10**20


def LI():
    return list(map(int, sys.stdin.buffer.readline().split()))


def I():
    return int(sys.stdin.buffer.readline())


def LS():
    return sys.stdin.buffer.readline().rstrip().decode("utf-8").split()


def S():
    return sys.stdin.buffer.readline().rstrip().decode("utf-8")


def IR(n):
    return [I() for i in range(n)]


def LIR(n):
    return [LI() for i in range(n)]


def SR(n):
    return [S() for i in range(n)]


def LSR(n):
    return [LS() for i in range(n)]


def SRL(n):
    return [list(S()) for i in range(n)]


mod = 1000000007
n, m = LI()
G = [[] for _ in range(n)]
for a, b, c in LIR(m):
    G[a - 1] += [(b - 1, c)]
# 負の閉路がなかったら高々n-1回で更新は終わるはずn回目に更新が起こったとしたら負の閉路がある。
def bellman_ford(G, s=0):
    n = len(G)
    dist = [-INF] * n
    dist[s] = 0
    v_nows = {s}
    for _ in range(n):
        v_changeds = set()
        for u in v_nows:
            for v, c in G[u]:
                if dist[u] + c > dist[v]:
                    dist[v] = dist[u] + c
                    v_changeds.add(v)
        v_nows = v_changeds
    if not v_changeds:
        return dist[n - 1]
    for i in v_nows:
        dist[i] = INF
    dq = deque(v_nows)
    while dq:
        u = dq.popleft()
        if u == n - 1:
            return "inf"
        for v, c in G[u]:
            if v == n - 1:
                return "inf"
            if dist[v] != INF:
                dist[v] = INF
                dq += [v]
    return dist[n - 1]


print((bellman_ford(G)))

-    if n - 1 in v_nows: -        return "inf" +        if u == n - 1: +            return "inf"