Dima and Inna love spending time together. The problem is, Seryozha isn't too enthusiastic to leave his room for some reason. But Dima and Inna love each other so much that they decided to get criminal...

Dima constructed a trap graph. He shouted: "Hey Seryozha, have a look at my cool graph!" to get his roommate interested and kicked him into the first node.

A trap graph is an undirected graph consisting of n nodes and m edges. For edge number k, Dima denoted a range of integers from lk to rk (lk ≤ rk). In order to get out of the trap graph, Seryozha initially (before starting his movements) should pick some integer (let's call it x), then Seryozha must go some way from the starting node with number 1 to the final node with number n. At that, Seryozha can go along edge k only if lk ≤ x ≤ rk.

Seryozha is a mathematician. He defined the loyalty of some path from the 1-st node to the n-th one as the number of integers x, such that if he initially chooses one of them, he passes the whole path. Help Seryozha find the path of maximum loyalty and return to his room as quickly as possible!

Input

The first line of the input contains two integers n and m (2 ≤ n ≤ 103, 0 ≤ m ≤ 3·103). Then follow m lines describing the edges. Each line contains four integers ak, bk, lk and rk (1 ≤ ak, bk ≤ n, 1 ≤ lk ≤ rk ≤ 106). The numbers mean that in the trap graph the k-th edge connects nodes ak and bk, this edge corresponds to the range of integers from lk to rk.

Note that the given graph can have loops and multiple edges.

Output

In a single line of the output print an integer — the maximum loyalty among all paths from the first node to the n-th one. If such paths do not exist or the maximum loyalty equals 0, print in a single line "Nice work, Dima!" without the quotes.

Examples

Input

4 4
1 2 1 10
2 4 3 5
1 3 1 5
2 4 2 7


Output

6


Input

5 6
1 2 1 10
2 5 11 20
1 4 2 5
1 3 10 11
3 4 12 10000
4 5 6 6


Output

Nice work, Dima!

Note

Explanation of the first example.

Overall, we have 2 ways to get from node 1 to node 4: first you must go along the edge 1-2 with range [1-10], then along one of the two edges 2-4. 

One of them contains range [3-5], that is, we can pass through with numbers 3, 4, 5. So the loyalty of such path is 3.

If we go along edge 2-4 with range [2-7], then we can pass through with numbers 2, 3, 4, 5, 6, 7. The loyalty is 6. That is the answer.

The edge 1-2 have no influence on the answer because its range includes both ranges of the following edges.
/** Micro Mezzo Macro Flation -- Overheated Economy ., Last Update: Feb. 12th 2013 **/ //{

/** Header .. **/ //{
#define LOCAL

#include <functional>
#include <algorithm>
#include <iostream>
#include <fstream>
#include <sstream>
#include <iomanip>
#include <numeric>
#include <cstring>
#include <cassert>
#include <cstdio>
#include <string>
#include <vector>
#include <bitset>
#include <queue>
#include <stack>
#include <cmath>
#include <ctime>
#include <list>
#include <set>
#include <map>

using namespace std;

#define REP(i, n) for (int i=0;i<int(n);++i)
#define FOR(i, a, b) for (int i=int(a);i<int(b);++i)
#define DWN(i, b, a) for (int i=int(b-1);i>=int(a);--i)
#define REP_1(i, n) for (int i=1;i<=int(n);++i)
#define FOR_1(i, a, b) for (int i=int(a);i<=int(b);++i)
#define DWN_1(i, b, a) for (int i=int(b);i>=int(a);--i)
#define REP_C(i, n) for (int n____=int(n),i=0;i<n____;++i)
#define FOR_C(i, a, b) for (int b____=int(b),i=a;i<b____;++i)
#define DWN_C(i, b, a) for (int a____=int(a),i=b-1;i>=a____;--i)
#define REP_N(i, n) for (i=0;i<int(n);++i)
#define FOR_N(i, a, b) for (i=int(a);i<int(b);++i)
#define DWN_N(i, b, a) for (i=int(b-1);i>=int(a);--i)
#define REP_1_C(i, n) for (int n____=int(n),i=1;i<=n____;++i)
#define FOR_1_C(i, a, b) for (int b____=int(b),i=a;i<=b____;++i)
#define DWN_1_C(i, b, a) for (int a____=int(a),i=b;i>=a____;--i)
#define REP_1_N(i, n) for (i=1;i<=int(n);++i)
#define FOR_1_N(i, a, b) for (i=int(a);i<=int(b);++i)
#define DWN_1_N(i, b, a) for (i=int(b);i>=int(a);--i)
#define REP_C_N(i, n) for (int n____=(i=0,int(n));i<n____;++i)
#define FOR_C_N(i, a, b) for (int b____=(i=0,int(b);i<b____;++i)
#define DWN_C_N(i, b, a) for (int a____=(i=b-1,int(a));i>=a____;--i)
#define REP_1_C_N(i, n) for (int n____=(i=1,int(n));i<=n____;++i)
#define FOR_1_C_N(i, a, b) for (int b____=(i=1,int(b);i<=b____;++i)
#define DWN_1_C_N(i, b, a) for (int a____=(i=b,int(a));i>=a____;--i)

#define ECH(it, A) for (__typeof(A.begin()) it=A.begin(); it != A.end(); ++it)
#define REP_S(i, str) for (char*i=str;*i;++i)
#define REP_L(i, hd, nxt) for (int i=hd;i;i=nxt[i])
#define REP_G(i, u) REP_L(i,hd[u],suc)
#define DO(n) for ( int ____n ## __line__ = n; ____n ## __line__ -- ; )
#define REP_2(i, j, n, m) REP(i, n) REP(j, m)
#define REP_2_1(i, j, n, m) REP_1(i, n) REP_1(j, m)
#define REP_3(i, j, k, n, m, l) REP(i, n) REP(j, m) REP(k, l)
#define REP_3_1(i, j, k, n, m, l) REP_1(i, n) REP_1(j, m) REP_1(k, l)
#define REP_4(i, j, k, ii, n, m, l, nn) REP(i, n) REP(j, m) REP(k, l) REP(ii, nn)
#define REP_4_1(i, j, k, ii, n, m, l, nn) REP_1(i, n) REP_1(j, m) REP_1(k, l) REP_1(ii, nn)

#define ALL(A) A.begin(), A.end()
#define LLA(A) A.rbegin(), A.rend()
#define CPY(A, B) memcpy(A, B, sizeof(A))
#define INS(A, P, B) A.insert(A.begin() + P, B)
#define ERS(A, P) A.erase(A.begin() + P)
#define BSC(A, x) (lower_bound(ALL(A), x) - A.begin())
#define CTN(T, x) (T.find(x) != T.end())
#define SZ(A) int(A.size())
#define PB push_back
#define MP(A, B) make_pair(A, B)
#define PTT pair<T, T>
#define fi first
#define se second

#define Rush for(int ____T=RD(); ____T--;)

#define Display(A, n, m) {                      \
	REP(i, n){		                            \
        REP(j, m) cout << A[i][j] << " ";       \
        cout << endl;				            \
	}						                    \
}

#define Display_1(A, n, m) {				    \
	REP_1(i, n){		                        \
        REP_1(j, m) cout << A[i][j] << " ";     \
		cout << endl;		            		\
	}						                    \
}

#pragma comment(linker, "/STACK:36777216")
//#pragma GCC optimize ("O2")
#define Ruby system("ruby main.rb")
#define Haskell system("runghc main.hs")
#define Python system("python main.py")
#define Pascal system("fpc main.pas")

typedef long long LL;
//typedef long double DB;
typedef double DB;
typedef unsigned UINT;
typedef unsigned long long ULL;

typedef vector<int> VI;
typedef vector<char> VC;
typedef vector<string> VS;
typedef vector<LL> VL;
typedef vector<DB> VF;
typedef set<int> SI;
typedef set<string> SS;
typedef map<int, int> MII;
typedef map<string, int> MSI;
typedef pair<int, int> PII;
typedef pair<LL, LL> PLL;
typedef vector<PII> VII;
typedef vector<VI> VVI;
typedef vector<VII> VVII;

template<class T> inline T& RD(T &);
template<class T> inline void OT(const T &);
inline LL RD(){LL x; return RD(x);}
inline DB& RF(DB &);
inline DB RF(){DB x; return RF(x);}
inline char* RS(char *s);
inline char& RC(char &c);
inline char RC();
inline char& RC(char &c){scanf(" %c", &c); return c;}
inline char RC(){char c; return RC(c);}
//inline char& RC(char &c){c = getchar(); return c;}
//inline char RC(){return getchar();}

template<class T> inline T& RDD(T &x){
    char c; for (c = getchar(); c < '-'; c = getchar());
    if (c == '-'){x = '0' - getchar(); for (c = getchar(); '0' <= c && c <= '9'; c = getchar()) x = x * 10 + '0' - c;}
    else {x = c - '0'; for (c = getchar(); '0' <= c && c <= '9'; c = getchar()) x = x * 10 + c - '0';}
    return x;
}

inline LL RDD(){LL x; return RDD(x);}

template<class T0, class T1> inline T0& RD(T0 &x0, T1 &x1){RD(x0), RD(x1); return x0;}
template<class T0, class T1, class T2> inline T0& RD(T0 &x0, T1 &x1, T2 &x2){RD(x0), RD(x1), RD(x2); return x0;}
template<class T0, class T1, class T2, class T3> inline T0& RD(T0 &x0, T1 &x1, T2 &x2, T3 &x3){RD(x0), RD(x1), RD(x2), RD(x3); return x0;}
template<class T0, class T1, class T2, class T3, class T4> inline T0& RD(T0 &x0, T1 &x1, T2 &x2, T3 &x3, T4 &x4){RD(x0), RD(x1), RD(x2), RD(x3), RD(x4); return x0;}
template<class T0, class T1, class T2, class T3, class T4, class T5> inline T0& RD(T0 &x0, T1 &x1, T2 &x2, T3 &x3, T4 &x4, T5 &x5){RD(x0), RD(x1), RD(x2), RD(x3), RD(x4), RD(x5); return x0;}
template<class T0, class T1, class T2, class T3, class T4, class T5, class T6> inline T0& RD(T0 &x0, T1 &x1, T2 &x2, T3 &x3, T4 &x4, T5 &x5, T6 &x6){RD(x0), RD(x1), RD(x2), RD(x3), RD(x4), RD(x5), RD(x6); return x0;}
template<class T0, class T1> inline void OT(const T0 &x0, const T1 &x1){OT(x0), OT(x1);}
template<class T0, class T1, class T2> inline void OT(const T0 &x0, const T1 &x1, const T2 &x2){OT(x0), OT(x1), OT(x2);}
template<class T0, class T1, class T2, class T3> inline void OT(const T0 &x0, const T1 &x1, const T2 &x2, const T3 &x3){OT(x0), OT(x1), OT(x2), OT(x3);}
template<class T0, class T1, class T2, class T3, class T4> inline void OT(const T0 &x0, const T1 &x1, const T2 &x2, const T3 &x3, const T4 &x4){OT(x0), OT(x1), OT(x2), OT(x3), OT(x4);}
template<class T0, class T1, class T2, class T3, class T4, class T5> inline void OT(const T0 &x0, const T1 &x1, const T2 &x2, const T3 &x3, const T4 &x4, const T5 &x5){OT(x0), OT(x1), OT(x2), OT(x3), OT(x4), OT(x5);}
template<class T0, class T1, class T2, class T3, class T4, class T5, class T6> inline void OT(const T0 &x0, const T1 &x1, const T2 &x2, const T3 &x3, const T4 &x4, const T5 &x5, const T6 &x6){OT(x0), OT(x1), OT(x2), OT(x3), OT(x4), OT(x5), OT(x6);}
inline char& RC(char &a, char &b){RC(a), RC(b); return a;}
inline char& RC(char &a, char &b, char &c){RC(a), RC(b), RC(c); return a;}
inline char& RC(char &a, char &b, char &c, char &d){RC(a), RC(b), RC(c), RC(d); return a;}
inline char& RC(char &a, char &b, char &c, char &d, char &e){RC(a), RC(b), RC(c), RC(d), RC(e); return a;}
inline char& RC(char &a, char &b, char &c, char &d, char &e, char &f){RC(a), RC(b), RC(c), RC(d), RC(e), RC(f); return a;}
inline char& RC(char &a, char &b, char &c, char &d, char &e, char &f, char &g){RC(a), RC(b), RC(c), RC(d), RC(e), RC(f), RC(g); return a;}
inline DB& RF(DB &a, DB &b){RF(a), RF(b); return a;}
inline DB& RF(DB &a, DB &b, DB &c){RF(a), RF(b), RF(c); return a;}
inline DB& RF(DB &a, DB &b, DB &c, DB &d){RF(a), RF(b), RF(c), RF(d); return a;}
inline DB& RF(DB &a, DB &b, DB &c, DB &d, DB &e){RF(a), RF(b), RF(c), RF(d), RF(e); return a;}
inline DB& RF(DB &a, DB &b, DB &c, DB &d, DB &e, DB &f){RF(a), RF(b), RF(c), RF(d), RF(e), RF(f); return a;}
inline DB& RF(DB &a, DB &b, DB &c, DB &d, DB &e, DB &f, DB &g){RF(a), RF(b), RF(c), RF(d), RF(e), RF(f), RF(g); return a;}
inline void RS(char *s1, char *s2){RS(s1), RS(s2);}
inline void RS(char *s1, char *s2, char *s3){RS(s1), RS(s2), RS(s3);}
template<class T0,class T1>inline void RDD(const T0&a, const T1&b){RDD(a),RDD(b);}
template<class T0,class T1,class T2>inline void RDD(const T0&a, const T1&b, const T2&c){RDD(a),RDD(b),RDD(c);}

template<class T> inline void RST(T &A){memset(A, 0, sizeof(A));}
template<class T> inline void FLC(T &A, int x){memset(A, x, sizeof(A));}
template<class T> inline void CLR(T &A){A.clear();}

template<class T0, class T1> inline void RST(T0 &A0, T1 &A1){RST(A0), RST(A1);}
template<class T0, class T1, class T2> inline void RST(T0 &A0, T1 &A1, T2 &A2){RST(A0), RST(A1), RST(A2);}
template<class T0, class T1, class T2, class T3> inline void RST(T0 &A0, T1 &A1, T2 &A2, T3 &A3){RST(A0), RST(A1), RST(A2), RST(A3);}
template<class T0, class T1, class T2, class T3, class T4> inline void RST(T0 &A0, T1 &A1, T2 &A2, T3 &A3, T4 &A4){RST(A0), RST(A1), RST(A2), RST(A3), RST(A4);}
template<class T0, class T1, class T2, class T3, class T4, class T5> inline void RST(T0 &A0, T1 &A1, T2 &A2, T3 &A3, T4 &A4, T5 &A5){RST(A0), RST(A1), RST(A2), RST(A3), RST(A4), RST(A5);}
template<class T0, class T1, class T2, class T3, class T4, class T5, class T6> inline void RST(T0 &A0, T1 &A1, T2 &A2, T3 &A3, T4 &A4, T5 &A5, T6 &A6){RST(A0), RST(A1), RST(A2), RST(A3), RST(A4), RST(A5), RST(A6);}
template<class T0, class T1> inline void FLC(T0 &A0, T1 &A1, int x){FLC(A0, x), FLC(A1, x);}
template<class T0, class T1, class T2> inline void FLC(T0 &A0, T1 &A1, T2 &A2, int x){FLC(A0, x), FLC(A1, x), FLC(A2, x);}
template<class T0, class T1, class T2, class T3> inline void FLC(T0 &A0, T1 &A1, T2 &A2, T3 &A3, int x){FLC(A0, x), FLC(A1, x), FLC(A2, x), FLC(A3, x);}
template<class T0, class T1, class T2, class T3, class T4> inline void FLC(T0 &A0, T1 &A1, T2 &A2, T3 &A3, T4 &A4, int x){FLC(A0, x), FLC(A1, x), FLC(A2, x), FLC(A3, x), FLC(A4, x);}
template<class T0, class T1, class T2, class T3, class T4, class T5> inline void FLC(T0 &A0, T1 &A1, T2 &A2, T3 &A3, T4 &A4, T5 &A5, int x){FLC(A0, x), FLC(A1, x), FLC(A2, x), FLC(A3, x), FLC(A4, x), FLC(A5, x);}
template<class T0, class T1, class T2, class T3, class T4, class T5, class T6> inline void FLC(T0 &A0, T1 &A1, T2 &A2, T3 &A3, T4 &A4, T5 &A5, T6 &A6, int x){FLC(A0, x), FLC(A1, x), FLC(A2, x), FLC(A3, x), FLC(A4, x), FLC(A5, x), FLC(A6, x);}
template<class T> inline void CLR(priority_queue<T, vector<T>, less<T> > &Q){while (!Q.empty()) Q.pop();}
template<class T> inline void CLR(priority_queue<T, vector<T>, greater<T> > &Q){while (!Q.empty()) Q.pop();}
template<class T0, class T1> inline void CLR(T0 &A0, T1 &A1){CLR(A0), CLR(A1);}
template<class T0, class T1, class T2> inline void CLR(T0 &A0, T1 &A1, T2 &A2){CLR(A0), CLR(A1), CLR(A2);}
template<class T0, class T1, class T2, class T3> inline void CLR(T0 &A0, T1 &A1, T2 &A2, T3 &A3){CLR(A0), CLR(A1), CLR(A2), CLR(A3);}
template<class T0, class T1, class T2, class T3, class T4> inline void CLR(T0 &A0, T1 &A1, T2 &A2, T3 &A3, T4 &A4){CLR(A0), CLR(A1), CLR(A2), CLR(A3), CLR(A4);}
template<class T0, class T1, class T2, class T3, class T4, class T5> inline void CLR(T0 &A0, T1 &A1, T2 &A2, T3 &A3, T4 &A4, T5 &A5){CLR(A0), CLR(A1), CLR(A2), CLR(A3), CLR(A4), CLR(A5);}
template<class T0, class T1, class T2, class T3, class T4, class T5, class T6> inline void CLR(T0 &A0, T1 &A1, T2 &A2, T3 &A3, T4 &A4, T5 &A5, T6 &A6){CLR(A0), CLR(A1), CLR(A2), CLR(A3), CLR(A4), CLR(A5), CLR(A6);}
template<class T> inline void CLR(T &A, int n){REP(i, n) CLR(A[i]);}

template<class T> inline T& SRT(T &A){sort(ALL(A)); return A;}
template<class T, class C> inline T& SRT(T &A, C B){sort(ALL(A), B); return A;}
template<class T> inline T& UNQ(T &A){A.resize(unique(ALL(SRT(A)))-A.begin());return A;}

//}

/** Constant List .. **/ //{

const int dx4[] = {-1, 0, 1, 0};
const int dy4[] = {0, 1, 0, -1};

const int dx8[] = {-1, 0, 1, 0 , -1 , -1 , 1 , 1};
const int dy8[] = {0, 1, 0, -1 , -1 , 1 , -1 , 1};

const int dxhorse[] = {-2 , -2 , -1 , -1 , 1 , 1 , 2 , 2};
const int dyhorse[] = {1 ,  -1 , 2  , -2 , 2 ,-2 , 1 ,-1};

const int MOD = 1000000007;
//int MOD = 99990001;
const int INF = 0x3f3f3f3f;
const LL INFF = 1LL << 60;
const DB EPS = 1e-9;
const DB OO = 1e15;
const DB PI = acos(-1.0); //M_PI;

//}

/** Add On .. **/ //{
// <<= '0. Nichi Joo ., //{
template<class T> inline void checkMin(T &a,const T b){if (b<a) a=b;}
template<class T> inline void checkMax(T &a,const T b){if (a<b) a=b;}
template<class T> inline void checkMin(T &a, T &b, const T x){checkMin(a, x), checkMin(b, x);}
template<class T> inline void checkMax(T &a, T &b, const T x){checkMax(a, x), checkMax(b, x);}
template <class T, class C> inline void checkMin(T& a, const T b, C c){if (c(b,a)) a = b;}
template <class T, class C> inline void checkMax(T& a, const T b, C c){if (c(a,b)) a = b;}
template<class T> inline T min(T a, T b, T c){return min(min(a, b), c);}
template<class T> inline T max(T a, T b, T c){return max(max(a, b), c);}
template<class T> inline T min(T a, T b, T c, T d){return min(min(a, b), min(c, d));}
template<class T> inline T max(T a, T b, T c, T d){return max(max(a, b), max(c, d));}
template<class T> inline T sqr(T a){return a*a;}
template<class T> inline T cub(T a){return a*a*a;}
inline int ceil(int x, int y){return (x - 1) / y + 1;}
inline int sgn(DB x){return x < -EPS ? -1 : x > EPS;}
inline int sgn(DB x, DB y){return sgn(x - y);}
//}
// <<= '1. Bitwise Operation ., //{
namespace BO{

inline bool _1(int x, int i){return bool(x&1<<i);}
inline bool _1(LL x, int i){return bool(x&1LL<<i);}
inline LL _1(int i){return 1LL<<i;}
inline LL _U(int i){return _1(i) - 1;};

inline int reverse_bits(int x){
    x = ((x >> 1) & 0x55555555) | ((x << 1) & 0xaaaaaaaa);
    x = ((x >> 2) & 0x33333333) | ((x << 2) & 0xcccccccc);
    x = ((x >> 4) & 0x0f0f0f0f) | ((x << 4) & 0xf0f0f0f0);
    x = ((x >> 8) & 0x00ff00ff) | ((x << 8) & 0xff00ff00);
    x = ((x >>16) & 0x0000ffff) | ((x <<16) & 0xffff0000);
    return x;
}

inline LL reverse_bits(LL x){
    x = ((x >> 1) & 0x5555555555555555LL) | ((x << 1) & 0xaaaaaaaaaaaaaaaaLL);
    x = ((x >> 2) & 0x3333333333333333LL) | ((x << 2) & 0xccccccccccccccccLL);
    x = ((x >> 4) & 0x0f0f0f0f0f0f0f0fLL) | ((x << 4) & 0xf0f0f0f0f0f0f0f0LL);
    x = ((x >> 8) & 0x00ff00ff00ff00ffLL) | ((x << 8) & 0xff00ff00ff00ff00LL);
    x = ((x >>16) & 0x0000ffff0000ffffLL) | ((x <<16) & 0xffff0000ffff0000LL);
    x = ((x >>32) & 0x00000000ffffffffLL) | ((x <<32) & 0xffffffff00000000LL);
    return x;
}

template<class T> inline bool odd(T x){return x&1;}
template<class T> inline bool even(T x){return !odd(x);}
template<class T> inline T low_bit(T x) {return x & -x;}
template<class T> inline T high_bit(T x) {T p = low_bit(x);while (p != x) x -= p, p = low_bit(x);return p;}
template<class T> inline T cover_bit(T x){T p = 1; while (p < x) p <<= 1;return p;}

inline int low_idx(int x){return __builtin_ffs(x);}
inline int low_idx(LL x){return __builtin_ffsll(x);}
inline int high_idx(int x){return low_idx(reverse_bits(x));}
inline int high_idx(LL x){return low_idx(reverse_bits(x));}
inline int clz(int x){return __builtin_clz(x);}
inline int clz(LL x){return __builtin_clzll(x);}
inline int ctz(int x){return __builtin_ctz(x);}
inline int ctz(LL x){return __builtin_ctzll(x);}
inline int parity(int x){return __builtin_parity(x);}
inline int parity(LL x){return __builtin_parityll(x);}
inline int lg2(int a){return 31 - clz(a);}
inline int lg2(LL a){return 63 - clz(a);}
inline int count_bits(int x){return __builtin_popcount(x);}
inline int count_bits(LL x){return __builtin_popcountll(x);}

} using namespace BO;//}
// <<= '2. Number Theory .,//{
namespace NT{
inline LL __lcm(LL a, LL b){return a*b/__gcd(a,b);}
inline void INC(int &a, int b){a += b; if (a >= MOD) a -= MOD;}
inline int sum(int a, int b){a += b; if (a >= MOD) a -= MOD; return a;}
inline void DEC(int &a, int b){a -= b; if (a < 0) a += MOD;}
inline int dff(int a, int b){a -= b; if (a < 0) a  += MOD; return a;}
inline void MUL(int &a, int b){a = (LL)a * b % MOD;}
inline int pdt(int a, int b){return (LL)a * b % MOD;}

inline int sum(int a, int b, int c){return sum(sum(a, b), c);}
inline int sum(int a, int b, int c, int d){return sum(sum(a, b), sum(c, d));}
inline int pdt(int a, int b, int c){return pdt(pdt(a, b), c);}
inline int pdt(int a, int b, int c, int d){return pdt(pdt(pdt(a, b), c), d);}

inline int pow(int a, int b){
    int c(1); while (b){
        if (b&1) MUL(c, a);
        MUL(a, a), b >>= 1;
    }
    return c;
}

inline int pow(int a, LL b){
    int c(1); while (b){
        if (b&1) MUL(c, a);
        MUL(a, a), b >>= 1;
    }
    return c;
}

template<class T> inline T pow(T a, LL b){
    T c(1); while (b){
        if (b&1) c *= a;
        a *= a, b >>= 1;
    }
    return c;
}

inline int _I(int b){
    int a = MOD, x1 = 0, x2 = 1, q;
    while (true){
        q = a / b, a %= b;
        if (!a) return (x2 + MOD) % MOD;
        DEC(x1, pdt(q, x2));

        q = b / a, b %= a;
        if (!b) return (x1 + MOD) % MOD;
        DEC(x2, pdt(q, x1));
    }
}

inline void DIV(int &a, int b){MUL(a, _I(b));}
inline int qtt(int a, int b){return pdt(a, _I(b));}

inline int phi(int n){
    int res = n; for (int i=2;sqr(i)<=n;++i) if (!(n%i)){
        DEC(res, qtt(res, i));
        do{n /= i;} while(!(n%i));
    }
    if (n != 1)
        DEC(res, qtt(res, n));
    return res;
}

} using namespace NT;//}
//}

/** Miscellaneous .. **/ //{
// <<= 'Random Event .. . //{
namespace RNG{
//srand((unsigned)time(NULL));
inline unsigned int rand16(){return ((rand()) << 15) ^ rand();}
inline unsigned int rand32(){return (rand16() << 16) | rand16();}
inline ULL rand64(){return ((LL)rand32() << 32) | rand32();}
inline ULL random(LL l, LL r){return l == r ? l : rand64() % (r - l) + l;}
int dice(){return rand() % 6;}
bool coin(){return bool(rand() % 2);}
} using namespace RNG;
//}
// <<= 'Clock .. . //{
namespace CLOCK{
DB s0, s1, rd, k, T;
inline DB getTime(){
#ifdef LOCAL
    return 1.0 * clock() / CLOCKS_PER_SEC;
#else
    timeval tv;
    gettimeofday(&tv, 0);
    return tv.tv_sec + tv.tv_usec * 1e-6;
#endif
}

inline void st0(DB _T = 0.98){T = _T, s0 = getTime();}
inline void st1(DB _k = 1.618){k = _k, s1 = getTime();}
inline void ed1(){rd = getTime() - s1;}
inline DB elapsed(){return getTime() - s0;}
inline bool safe(){return elapsed() + rd * k < T;}
} //using namespace CLOCK;
//}
// <<= 'Temp .. . //{
namespace TMP{
template<class T> PTT operator+(const PTT &p1, const PTT &p2) {
	return PTT(p1.fi + p2.fi, p1.se + p2.se);
}

template<class T> PTT operator-(const PTT &p1, const PTT &p2) {
	return PTT(p1.fi - p2.fi, p1.se - p2.se);
}

template<class T> PTT operator*(const PTT &lhs, T k){
    return PTT(lhs.fi * k, lhs.se * k);
}
} using namespace TMP;
//}
//}

/** Algorithm    .. */ //{
// <<= '-. Math .,//{
namespace Math{
	typedef long long typec;
	///Lib functions
	typec GCD(typec a, typec b)
	{
		return b ? GCD(b, a % b) : a;
	}
	typec extendGCD(typec a, typec b, typec& x, typec& y)
	{
		if(!b) return x = 1, y = 0, a;
		typec res = extendGCD(b, a % b, x, y), tmp = x;
		x = y, y = tmp - (a / b) * y;
		return res;
	}
	///for x^k
	typec power(typec x, typec k)
	{
		typec res = 1;
		while(k)
		{
			if(k&1) res *= x;
			x *= x, k >>= 1;
		}
		return res;
	}
	///for x^k mod m
	typec powerMod(typec x, typec k, typec m)
	{
		typec res = 1;
		while(x %= m, k)
		{
			if(k&1) res *= x, res %= m;
			x *= x, k >>=1;
		}
		return res;
	}
	/***************************************
	Inverse in mod p^t system
	***************************************/
	typec inverse(typec a, typec p, typec t = 1)
	{
		typec pt = power(p, t);
		typec x, y;
	    y = extendGCD(a, pt, x, y);
		return x < 0 ? x += pt : x;
	}
	/***************************************
	Linear congruence theorem
	x = a (mod p)
	x = b (mod q)
	for gcd(p, q) = 1, 0 <= x < pq
	***************************************/
	typec linearCongruence(typec a, typec b, typec p, typec q)
	{
		typec x, y;
		y = extendGCD(p, q, x, y);
		while(b < a) b += q / y;
		x *= b - a, x = p * x + a, x %= p * q;
		if(x < 0) x += p * q;
		return x;
	}
	/***************************************
	prime table
	O(n)
	***************************************/
	const int PRIMERANGE = 1000000;
	int prime[PRIMERANGE + 1];
	int mobius[PRIMERANGE + 1];
	int getPrime()
	{
		memset (prime, 0, sizeof (int) * (PRIMERANGE + 1));
		memset(mobius , 0 , sizeof(mobius));
		mobius[1] = 1;
		for (int i = 2; i <= PRIMERANGE; i++)
		{
			if (!prime[i]) prime[++prime[0]] = i , mobius[i] = -1;
			for (int j = 1; j <= prime[0] && prime[j] <= PRIMERANGE / i; j++)
			{
				prime[prime[j]*i] = 1;
				if (i % prime[j] == 0) break;
				else mobius[i * prime[j]] = -mobius[i];
			}
		}
		return prime[0];
	}
	/***************************************
	get factor of n
	O(sqrt(n))
	factor[][0] is prime factor
	factor[][1] is factor generated by this prime
	factor[][2] is factor counter

	need: Prime Table
	***************************************/
	///you should init the prime table before
	int factor[100][3], facCnt;
	int getFactors(int x)
	{
		facCnt = 0;
		int tmp = x;
		for(int i = 1; prime[i] <= tmp / prime[i]; i++)
		{
			factor[facCnt][1] = 1, factor[facCnt][2] = 0;
			if(tmp % prime[i] == 0)
				factor[facCnt][0] = prime[i];
			while(tmp % prime[i] == 0)
				factor[facCnt][2]++, factor[facCnt][1] *= prime[i], tmp /= prime[i];
			if(factor[facCnt][1] > 1) facCnt++;
		}
		if(tmp != 1)
			factor[facCnt][0] = tmp, factor[facCnt][1] = tmp, factor[facCnt++][2] = 1;
		return facCnt;
	}
	typec combinationModP(typec n, typec k, typec p)
	{
		if(k > n) return 0;
		if(n - k < k) k = n - k;
		typec a = 1, b = 1, x, y;
		int pcnt = 0;
		for(int i = 1; i <= k; i++)
		{
			x = n - i + 1, y = i;
			while(x % p == 0) x /= p, pcnt++;
			while(y % p == 0) y /= p, pcnt--;
			x %= p, y %= p, a *= x, b *= y;
			b %= p, a %= p;
		}
		if(pcnt) return 0;
		extendGCD(b, p, x, y);
		if(x < 0) x += p;
		a *= x, a %= p;
		return a;
	}
};//using namespace Math;
//}
// <<= '-. Geo ,.//{
namespace Geo{
	#define typec double
    const typec eps=1e-9;
    int dblcmp(double d){
        if (fabs(d)<eps)return 0;
        return d>eps?1:-1;
    }
    int sgn(double a) {return a<-eps?-1:a>eps;}
    inline double sqr(double x){return x*x;}
    struct Point2D{
		typec x,y;
		Point2D(){}
		Point2D(typec _x,typec _y):x(_x),y(_y){};
		void input(){
			scanf("%lf%lf",&x,&y);
		}
		void output(){
			printf("%.2f %.2f\n",x,y);
		}
		bool operator==(Point2D a)const{
			return dblcmp(a.x-x)==0&&dblcmp(a.y-y)==0;
		}
		bool operator<(Point2D a)const{
			return dblcmp(a.x-x)==0?dblcmp(y-a.y)<0:x<a.x;
		}
		typec len(){
			return hypot(x,y);
		}
		typec len2(){
			return x*x+y*y;
		}
		Point2D operator + (const Point2D &A) const{
			return Point2D(x + A.x , y + A.y);
		}
		Point2D operator - (const Point2D &A) const{
			return Point2D(x - A.x , y - A.y);
		}
		Point2D operator * (const typec _x) const{
			return Point2D(x * _x , y * _x);
		}
		typec operator * (const Point2D &A) const{
			return x * A.x + y * A.y;
		}
		typec operator ^ (const Point2D &A) const{
			return x * A.y - y * A.x;
		}
		Point2D operator / (const typec _p) const{
			return Point2D(x / _p , y / _p);
		}
		typec distance(Point2D p){
			return hypot(x-p.x,y-p.y);
		}
		Point2D add(Point2D p){
			return Point2D(x+p.x,y+p.y);
		}
		Point2D sub(Point2D p){
			return Point2D(x-p.x,y-p.y);
		}
		Point2D mul(typec b){
			return Point2D(x*b,y*b);
		}
		Point2D div(typec b){
			return Point2D(x/b,y/b);
		}
		typec dot(Point2D p){
			return x*p.x+y*p.y;
		}
		typec det(Point2D p){
			return x*p.y-y*p.x;
		}
		typec rad(Point2D a,Point2D b){
			Point2D p=*this;
			return fabs(atan2(fabs(a.sub(p).det(b.sub(p))),a.sub(p).dot(b.sub(p))));
		}
		Point2D trunc(typec r){
			typec l=len();
			if (!dblcmp(l))return *this;
			r/=l;
			return Point2D(x*r,y*r);
		}
		Point2D rotleft(){
			return Point2D(-y,x);
		}
		Point2D rotright(){
			return Point2D(y,-x);
		}
		Point2D rotate(Point2D p,typec angle)//ÈÆµãpÄæÊ±ÕëÐý×ªangle½Ç¶È
		{
			Point2D v=this->sub(p);
			typec c=cos(angle),s=sin(angle);
			return Point2D(p.x+v.x*c-v.y*s,p.y+v.x*s+v.y*c);
		}
	};

	typec cross(Point2D a,Point2D b,Point2D c){
		return (b.sub(a)).det(c.sub(a));
	}
}using namespace Geo;
//}
//}

/** I/O Accelerator Interface .. **/ //{
template<class T> inline T& RD(T &x){
    //cin >> x;
    //scanf("%d", &x);
    char c; for (c = getchar(); c < '0'; c = getchar()); x = c - '0'; for (c = getchar(); '0' <= c && c <= '9'; c = getchar()) x = x * 10 + c - '0';
    //char c; c = getchar(); x = c - '0'; for (c = getchar(); c >= '0'; c = getchar()) x = x * 10 + c - '0';
    return x;
}

inline DB& RF(DB &x){
    //cin >> x;
    scanf("%lf", &x);
    /*char t; while ((t=getchar())==' '||t=='\n'); x = t - '0';
    while ((t=getchar())!=' '&&t!='\n'&&t!='.')x*=10,x+=t-'0';
    if (t=='.'){DB l=1; while ((t=getchar())!=' '&&t!='\n')l*=0.1,x += (t-'0')*l;}*/
    return x;
}

inline char* RS(char *s){
    //gets(s);
    scanf("%s", s);
    return s;
}

int Case; template<class T> inline void OT(const T &x){
    //printf("Case %d: %d\n", ++Case, x);
    //printf("%.2lf\n", x);
    //printf("%d\n", x);
    cout << x << endl;
}
//}
/* .................................................................................................................................. */
const int N = 1009;
struct Edge{
    int l , r , v;
};
vector<Edge> edge[N];
VI hash;
queue<int> q;
int n , m;
int vis[N];
int check(int x){
    while(!q.empty()) q.pop();
    Case++;
    q.push(1);
    for (int i = 1 ; i <= n ; ++i) vis[i] = INF;
    vis[1] = x;
    while(!q.empty()){
        int now = q.front() , go;
        q.pop();
        for (int i = 0 ; i < SZ(edge[now]) ; ++i) if (edge[now][i].l <= x && x <= edge[now][i].r){
            int res = min(vis[now] , edge[now][i].l);
            if (vis[edge[now][i].v] <= res) continue;
            vis[edge[now][i].v] = res;
            q.push(edge[now][i].v);
        }
    }
    return vis[n];
}

bool oknode[N] , okinterval[N];
int main(){
    Case = 0;
    cin >> n >> m;
    if (m == 0){
        cout << "Nice work, Dima!" << endl;
        return 0;
    }
    DO(m){
        int x , y , l , r;
        RD(x , y , l , r);
        Edge me;
        me.l = l , me.r = r , me.v = y;
        edge[x].PB(me);
        me.v = x;
        edge[y].PB(me);
        hash.PB(l);hash.PB(r);
    }
    UNQ(hash);
    int ans = 0;
    for (int i = 0 ; i < SZ(hash) ; ++i){
        int res = check(hash[i]);
        checkMax(ans , max(0 , hash[i] - res));
    }

    if (ans == 0) puts("Nice work, Dima!");
    else OT(ans);
}



