1+ import sys
2+ input = sys .stdin .readline
3+ 4+ def find_parent (parent , x ):
5+ if parent [x ] != x :
6+ parent [x ] = find_parent (parent , parent [x ])
7+ return parent [x ]
8+ 9+ def union_parent (parent , a , b ):
10+ a = find_parent (parent , a )
11+ b = find_parent (parent , b )
12+ if a < b :
13+ parent [b ] = a
14+ else :
15+ parent [a ] = b
16+ 17+ n , m = map (int , input ().split ())
18+ 19+ graph = []
20+ parent = [x for x in range (n + 1 )]
21+ 22+ for _ in range (m + 1 ):
23+ a , b , c = map (int , input ().split ())
24+ if c == 0 : # 오르막길
25+ graph .append ((1 , a , b ))
26+ else :
27+ graph .append ((0 , a , b ))
28+ 29+ # 최솟값 구하기
30+ graph .sort ()
31+ Min = 0
32+ 33+ for edge in graph :
34+ c , a , b = edge
35+ if find_parent (parent , a ) != find_parent (parent , b ):
36+ union_parent (parent , a , b )
37+ Min += c
38+ 39+ # 최댓값 구하기
40+ parent = [x for x in range (n + 1 )]
41+ Max = 0
42+ graph .sort (reverse = True )
43+ for edge in graph :
44+ c , a , b = edge
45+ if find_parent (parent , a ) != find_parent (parent , b ):
46+ union_parent (parent , a , b )
47+ Max += c
48+ 49+ # A^2 - B^2 = (A + B)(A - B) 이용. (단, A >= B)
50+ print ((Max + Min ) * (Max - Min ))
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