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#include <cstdio>
#include <iostream>
#include <cstring>
#include <cmath>
#include <algorithm>
using namespace std;
const int INF = 1<<30;
typedef long long LL;
const int N = 160005;
struct edge_type {
	int x, y, a, b;
} edge[N];
int getint() {
	int r=0,k=1; char c=getchar();
	for(;'0'>c||c>'9';c=getchar()) if(c=='-')k=-1;
	for(;'0'<=c&&c<='9';c=getchar()) r=r*10-'0'+c;
	return r*k;
}
bool cmpa(edge_type x, edge_type y) {
	return x.a<y.a;
}
int c[N][2], fa[N], mx[N], rev[N], mxid[N], st[N], p[N];
bool isroot(int x) { return !(c[fa[x]][0]==x||c[fa[x]][1]==x); }
void pd(int x) {
	int &l = c[x][0], &r = c[x][1];
	if (rev[x]) {
		rev[x] = 0; rev[l] ^= 1; rev[r] ^= 1;
		swap(l, r);
	}
}
void pu(int x) {
	int &l = c[x][0], &r = c[x][1];
	if (mx[l] > mx[r]) {
		mx[x] = mx[l];
		mxid[x] = mxid[l];
	} else {
		mx[x] = mx[r];
		mxid[x] = mxid[r];
	}
	if (p[x] > mx[x]) {
		mx[x] = p[x];
		mxid[x] = x;
	}
}
void rotate(int x) {
	int y = fa[x], z = fa[y], a=(c[y][1]==x), b=!a;
	if (!isroot(y)) c[z][c[z][1]==y]=x;
	fa[x]=z; fa[y]=x; fa[c[x][b]]=y;
	c[y][a]=c[x][b]; c[x][b]=y;
	pu(y); pu(x);
}
void splay(int x) {
	int t = 1; st[1] = x;
	for (int i = x; !isroot(i); i = fa[i]) st[++t] = fa[i];
	while (t) pd(st[t--]);
	while (!isroot(x)) {
		int y = fa[x], z = fa[y];
		if (!isroot(y)) {
			if (c[z][0]==y^c[y][0]==x) rotate(x);
			else rotate(y);
		}
		rotate(x);
	}
}
void access(int x) {
	int y = 0;
	while (x) {
		splay(x);
		c[x][1] = y;
		pu(x);
		y = x;
		x = fa[x];
	}
}
void mkrt(int x) {
	access(x);
	splay(x);
	rev[x] ^= 1;
}
void link(int x, int y) {
	mkrt(x);
	fa[x] = y;
	splay(x);
}
void cut(int x, int y) {
	mkrt(x);
	access(y);
	splay(y);
	fa[x] = 0;
	c[y][0] = 0;
}
int findrt(int x) {
	access(x);
	splay(x);
	while (c[x][0]) x = c[x][0];
	return x;
}
void add(int eid) {
	int x = edge[eid].x, y = edge[eid].y;
	if (findrt(x) != findrt(y)) {
		link(x, eid+50006);
		link(eid+50006, y);
		return;
	}
	mkrt(x); access(y); splay(y);
	if (mx[y] <= edge[eid].b) return;
	int tmp = mxid[y];
	cut(edge[tmp-50006].x, tmp);
	cut(tmp, edge[tmp-50006].y);
	link(x, eid+50006);
	link(y, eid+50006);
}
int query(int x, int y) {
	if (findrt(x) != findrt(y)) return INF;
	mkrt(x); access(y); splay(y);
	return mx[y];
}
int n, m, ans = INF;
int main () {
	n=getint(); m=getint();
	for (int i = 1; i <= m; ++i) {
		edge[i].x=getint();
		edge[i].y=getint();
		edge[i].a=getint();
		edge[i].b=getint();
	}
	sort(edge+1, edge+m+1, cmpa);
	for (int i = 1; i <= m; ++i) p[i+50006] = edge[i].b;
	for (int i = 1; i <= m; ++i) {
		add(i);
		ans = min(ans, query(1,n)+edge[i].a);
	}
	if (ans == INF) printf("-1");
	else printf("%d", ans);
}