You need to find a spanning tree in the graph so that the difference between the maximal and the minimal edges is minimal.

The first line of the input contains two integers $n,m\ (2 ≤n≤ 1000,\ 0 ≤m≤ 10,000)$ — the number of vertices and the number of edges, respectively. 

Next $m$ lines contain the description of edges, one per line. Edge $i$ is described by three integers $b_i, e_i,w_i\ (1 ≤b_i,e_i≤n,\ - 10^9 ≤w_i≤ 10^9)$ — the ends of the edge and its weight, respectively.

If the spanning tree exists, then the first line of the output should contain "YES", and the second line should contain one integer — the minimal difference between the maximal and the minimal edges of the spanning tree.

Otherwise, the sole line of the output should contain "NO".