#include <bits/stdc++.h>

using namespace std;

using int64 = long long;
const int mod = 1e9 + 7;
//const int mod = 998244353;

const int64 infll = (1LL << 62) - 1;
const int inf = (1 << 30) - 1;

struct IoSetup {
  IoSetup() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);
    cerr << fixed << setprecision(10);
  }
} iosetup;


template< typename T1, typename T2 >
ostream &operator<<(ostream &os, const pair< T1, T2 > &p) {
  os << p.first << " " << p.second;
  return os;
}

template< typename T1, typename T2 >
istream &operator>>(istream &is, pair< T1, T2 > &p) {
  is >> p.first >> p.second;
  return is;
}

template< typename T >
ostream &operator<<(ostream &os, const vector< T > &v) {
  for(int i = 0; i < (int) v.size(); i++) {
    os << v[i] << (i + 1 != v.size() ? " " : "");
  }
  return os;
}

template< typename T >
istream &operator>>(istream &is, vector< T > &v) {
  for(T &in : v) is >> in;
  return is;
}

template< typename T1, typename T2 >
inline bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); }

template< typename T1, typename T2 >
inline bool chmin(T1 &a, T2 b) { return a > b && (a = b, true); }

template< typename T = int64 >
vector< T > make_v(size_t a) {
  return vector< T >(a);
}

template< typename T, typename... Ts >
auto make_v(size_t a, Ts... ts) {
  return vector< decltype(make_v< T >(ts...)) >(a, make_v< T >(ts...));
}

template< typename T, typename V >
typename enable_if< is_class< T >::value == 0 >::type fill_v(T &t, const V &v) {
  t = v;
}

template< typename T, typename V >
typename enable_if< is_class< T >::value != 0 >::type fill_v(T &t, const V &v) {
  for(auto &e : t) fill_v(e, v);
}

template< typename F >
struct FixPoint : F {
  FixPoint(F &&f) : F(forward< F >(f)) {}

  template< typename... Args >
  decltype(auto) operator()(Args &&... args) const {
    return F::operator()(*this, forward< Args >(args)...);
  }
};

template< typename F >
inline decltype(auto) MFP(F &&f) {
  return FixPoint< F >{forward< F >(f)};
}

template< typename T = int >
struct Edge {
  int from, to;
  T cost;
  int idx;

  Edge() = default;

  Edge(int from, int to, T cost = 1, int idx = -1) : from(from), to(to), cost(cost), idx(idx) {}

  operator int() const { return to; }
};

template< typename T = int >
struct Graph {
  vector< vector< Edge< T > > > g;
  int es;

  Graph() = default;

  explicit Graph(int n) : g(n), es(0) {}

  size_t size() const {
    return g.size();
  }

  void add_directed_edge(int from, int to, T cost = 1) {
    g[from].emplace_back(from, to, cost, es++);
  }

  void add_edge(int from, int to, T cost = 1) {
    g[from].emplace_back(from, to, cost, es);
    g[to].emplace_back(to, from, cost, es++);
  }

  void read(int M, int padding = -1, bool weighted = false, bool directed = false) {
    for(int i = 0; i < M; i++) {
      int a, b;
      cin >> a >> b;
      a += padding;
      b += padding;
      T c = T(1);
      if(weighted) cin >> c;
      if(directed) add_directed_edge(a, b, c);
      else add_edge(a, b, c);
    }
  }
};

template< typename T = int >
using Edges = vector< Edge< T > >;

/**
 * @brief Bellman-Ford(単一始点最短路)
 */
template< typename T >
vector< T > bellman_ford(const Edges< T > &edges, int V, int s) {
  const auto INF = numeric_limits< T >::max();
  vector< T > dist(V, INF);
  dist[s] = 0;
  for(int i = 0; i < V - 1; i++) {
    for(auto &e : edges) {
      if(dist[e.from] == INF) continue;
      dist[e.to] = min(dist[e.to], dist[e.from] + e.cost);
    }
  }
  for(auto &e : edges) {
    if(dist[e.from] == INF) continue;
    if(dist[e.from] + e.cost < dist[e.to]) return vector< T >();
  }
  return dist;
}

int main() {
  int N, C;
  int A[200], O[200], B[200], S[200], D[200];

  cin >> N >> C;
  vector< int > undefined;
  for(int i = 0; i < C; i++) {
    string str;
    cin >> str;
    int tail = 0, a = 0, b = 0, o, s, d = 0;
    while(isdigit(str[tail])) a = a * 10 + str[tail++] - '0';
    if(str[tail] == '*') o = 2;
    else if(str[tail] == '<') o = 0, ++tail;
    else o = 1, ++tail;
    ++tail;
    while(isdigit(str[tail])) b = b * 10 + str[tail++] - '0';
    if(str[tail] == '+') s = 0;
    else s = 1;
    ++tail;
    while(tail < str.size()) d = d * 10 + str[tail++] - '0';
    A[i] = --a, B[i] = --b, O[i] = o, S[i] = s, D[i] = d;
    if(o == 2) undefined.push_back(i);
  }
  int ret = -1;
  for(int i = 0; i < (1 << undefined.size()); i++) {
    for(int j = 0; j < undefined.size(); j++) O[undefined[j]] = (i >> j) & 1;

    Edges<> es;
    for(int k = 0; k < C; k++) {
      if(O[k] == 1) swap(A[k], B[k]);
      es.emplace_back(B[k], A[k], 0);
      if(S[k] == 0) es.emplace_back(B[k], A[k], -D[k]);
      else es.emplace_back(A[k], B[k], D[k]);
      if(O[k] == 1) swap(A[k], B[k]);
    }
    auto dists = bellman_ford(es, N, 0);
    if(dists.empty() || *min_element(begin(dists), end(dists)) < 0) continue;
    ret = max(ret, *max_element(begin(dists), end(dists)));
  }

  if(ret >= numeric_limits< int >::max()) cout << "inf" << endl;
  else cout << ret << endl;
}



Measured memory_bytes: 3212