import java.io.*
import java.util.*
import java.lang.*
import java.lang.Math.*


class Bellman(val eg: Array<ArrayList<To>>, val start: Int) {
    private var dist = LongArray(0)
    init {
        val N = eg.size
        dist = LongArray(N){LINF}
        dist[start] = 0L
        for (i in 0 until N-1) {
            var updating = false
            for (x in 0 until N) {
                for (t in eg[x]) {
                    val y = t.idx
                    if (dist[x] + t.cost < dist[y]) {
                        dist[y] = dist[x] + t.cost
                        updating = true
                    }
                }
            }
            if (!updating) break
        }
    }
    private fun hasNegativeCycle(i: Int): Boolean {
        val N = eg.size
        val ndst = dist.clone()
        for (x in 0 until N)  {
            for (t in eg[x]) {
                val y = t.idx
                if (ndst[x] + t.cost < ndst[y]) {
                    ndst[y] = ndst[x] + t.cost
                }
            }
        }
        return ndst[i] != dist[i]
    }
    fun distance(i: Int): Long{
        return if(hasNegativeCycle(i)) -LINF else dist[i]
    }
}

fun solve() {
    val (N, M) = rd.readIntArray()
    val eg = edge<To>(N)
    for (i in 0 until M) {
        var (a, b, c) = rd.readIntArray()
        a--; b--
        eg[a].add(To(b, -c.toLong()))
    }

    val bf = Bellman(eg, 0)

    val res = -bf.distance(N-1)
    val ans = if (res>=LINF) "inf" else res.toString()
    println(ans)
}


//val rd = debug.Reader("abc", "061", "d", "sample-1")
val rd = Reader()


fun main(args: Array<String>) {
    try {
        var exception: Throwable? = null
        val sth = Thread(null, SolveThread(), "solveThread", 128 * 1024 * 1024)
        sth.setUncaughtExceptionHandler { _, e -> exception = e }
        sth.start(); sth.join()
        if (exception != null) throw exception!!
    } catch (e: Exception) { throw e }
}
const val MOD = 1_000_000_007L; const val INF = Int.MAX_VALUE/2; const val LINF = Long.MAX_VALUE/2
val EPS = 1e-9; fun DBLEQ(a: Double, b: Double): Boolean {return abs(a - b) < EPS}
data class IntPair(val first: Int, val second: Int); data class LongPair(val first: Long, val second: Long)
data class To(val idx: Int, val cost: Long)
fun <T>edge(V: Int): Array<ArrayList<T>> { return Array(V){ArrayList<T>()} }
val errPrintln: (Any) -> Unit = { msg -> System.err.println(msg) }
fun rAssert(exp: Boolean, lazyMsg: () -> String = {""}) {
    if (!exp) { val msg = lazyMsg(); errPrintln("EAssert Error: $msg"); throw Error(msg) }
}
fun tAssert(exp: Boolean, lazyMsg: () -> String = {""}) {
    if (!exp) { val msg = lazyMsg(); errPrintln("TAssert Error: $msg"); Thread.sleep(3000) }
}
class SolveThread : Runnable {
    override fun run() { solve() }
}
class Reader {
    private val br = BufferedReader(InputStreamReader(System.`in`))
    val readString: () -> String = { br.readLine() }
    val readInt: () -> Int = { br.readLine().toInt() }
    val readLong: () -> Long = { br.readLine().toLong() }
    val readIntArray: () -> IntArray = { br.readLine().split(' ').map { it.toInt() }.toIntArray() }
    val readLongArray: () -> LongArray = { br.readLine().split(' ').map { it.toLong() }.toLongArray() }
    val readListInt: () -> List<Int> = { br.readLine().split(' ').map { it.toInt() } }
    val readListLong: () -> List<Long> = { br.readLine().split(' ').map { it.toLong() } }
}


Measured memory_bytes: 53956