#include<bits/stdc++.h>
using namespace std;
#define int long long
#define ii pair <int, int>
#define app push_back
#define all(a) a.begin(), a.end()
#define bp __builtin_popcountll
#define ll long long
#define mp make_pair
#define x first
#define y second
#define Time (double)clock()/CLOCKS_PER_SEC
#define debug(x) std::cout << #x << ": " << x << '\n';
#define FOR(i, n) for (int i = 0; i < n; ++i)
#define pb push_back
#define trav(a, x) for (auto& a : x)
using vi = vector<int>;
template <typename T>
std::ostream& operator <<(std::ostream& output, const pair <T, T> & data)
{
    output << "(" << data.x << "," << data.y << ")";
    return output;
}
template <typename T>
std::ostream& operator <<(std::ostream& output, const std::vector<T>& data)
{
    for (const T& x : data)
        output << x << " ";
    return output;
}
ll div_up(ll a, ll b) { return a/b+((a^b)>0&&a%b); } // divide a by b rounded up
ll div_down(ll a, ll b) { return a/b-((a^b)<0&&a%b); } // divide a by b rounded down 
#define tcT template<class T
#define tcTU tcT, class U
tcT> using V = vector<T>; 
tcT> void re(V<T>& x) { 
    trav(a, x)
        cin >> a;
}
tcT> bool ckmin(T& a, const T& b) {
    return b < a ? a = b, 1 : 0; 
} // set a = min(a,b)
tcT> bool ckmax(T& a, const T& b) {
    return a < b ? a = b, 1 : 0; 
}

//need define int long long
namespace Stuff {
const int MOD = 1e9+7;
int mod(int n) {
    n %= MOD;
    if (n < 0) return n + MOD;
    else return n;
}   
int fp(int a, int p) {
    int ans = 1, c = a;
    for (int i = 0; (1ll << i) <= p; ++i) {
        if ((p >> i) & 1) ans = mod(ans * c);
        c = mod(c * c);
    }   
    return ans;
}   
int dv(int a, int b) { return mod(a * fp(b, MOD - 2)); }
};
struct M {
ll x;
M (int x_) { x = Stuff::mod(x_); }   
M () { x = 0; }
M operator + (M y) {
    int ans = x + y.x;
    if (ans >= Stuff::MOD)
        ans -= Stuff::MOD;
    return M(ans);
}
M operator - (M y) {
    int ans = x - y.x;
    if (ans < 0)
        ans += Stuff::MOD;
    return M(ans);            
}   
M operator * (M y) { return M(x * y.x % Stuff::MOD); }   
M operator / (M y) { return M(x * Stuff::fp(y.x, Stuff::MOD - 2) % Stuff::MOD); }   
M operator + (int y) { return (*this) + M(y); }
M operator - (int y) { return (*this) - M(y); }   
M operator * (int y) { return (*this) * M(y); }   
M operator / (int y) { return (*this) / M(y); }   
M operator ^ (int p) { return M(Stuff::fp(x, p)); }   
void operator += (M y) { *this = *this + y; }   
void operator -= (M y) { *this = *this - y; }   
void operator *= (M y) { *this = *this * y; }
void operator /= (M y) { *this = *this / y; }   
void operator += (int y) { *this = *this + y; }   
void operator -= (int y) { *this = *this - y; }   
void operator *= (int y) { *this = *this * y; }
void operator /= (int y) { *this = *this / y; }   
void operator ^= (int p) { *this = *this ^ p; }
bool operator == (M y) { return x == y.x; }
};  
std::ostream& operator << (std::ostream& o, const M& a)
{
    cout << a.x;
    return o;
}

const int N = 1e5+7;
V <vi> g[N];
vi gr[N], rg[N];
bool del[N];

bool used[N];
void dfs(int u, vi g[N]) {
    used[u] = 1;
    for (int v : g[u])
        if (!used[v])   
            dfs(v, g);
}    

vi top;
int pos[N];
void jfs(int u) {
    used[u] = 1;
    for (auto v : gr[u]) {
        if (!used[v]) {
            jfs(v);
        }   
    }   
    top.app(u);
}   

int n;
M cnt[N], sum[N];
void calc(int u) {
    used[u] = 1;

    if (u == n) {
        sum[u] = 0;
        cnt[u] = 1;

    /*
    debug(u);
    debug(cnt[u]);
    debug(sum[u]);
    */

        return;
    }   

    for (auto e : g[u]) {
        int v = e[0];
        int l = e[1];
        int a = e[2];
        if (!used[v]) {
            calc(v);
        }   
        cnt[u] += cnt[v] * a;
        sum[u] += sum[v] * a + cnt[v] * a * l;
    }   
    /*
    debug(u);
    debug(cnt[u]);
    debug(sum[u]);
    */
}   

signed main() {
    #ifdef HOME
    freopen("input.txt", "r", stdin);
    #else
    #define endl '\n'
    ios_base::sync_with_stdio(0); cin.tie(0);
    #endif
    int m;
    cin >> n >> m;
    FOR (i, m) {
        int u, v, l, a;
        cin >> u >> v >> l >> a;
        g[u].app({v, l, a});
        gr[u].app(v);
        rg[v].app(u);
    }   
    dfs(0, gr);
    FOR (i, n + 1) {
        if (!used[i])
            del[i] = 1;
    }   
    memset(used, 0, sizeof used);
    dfs(n, rg);
    FOR (i, n + 1) {
        if (!used[i])
            del[i] = 1;
    }   
    if (del[0] || del[n]) {
        cout << 0 << endl;
        exit(0);
    }   
    memset(used, 0, sizeof used);
    jfs(0);
    reverse(all(top));
    FOR (i, (int)top.size())
        pos[top[i]] = i;

    FOR (u, n + 1)
        trav(v, gr[u])
            if (pos[u] > pos[v]) {
                cout << "INF" << endl;
                exit(0);
            }   

    memset(used, 0, sizeof used);
    calc(0);
    cout << sum[0] << endl;
}