import sys
input = sys.stdin.readline
from operator import itemgetter

mod = 10**9+7

N,M,X=map(int,input().split())

E=[tuple(map(int,input().split())) for i in range(M)]

E.sort(key=itemgetter(2))

# UnionFind

Group = [i for i in range(N+1)] # グループ分け
Nodes = [1]*(N+1) # 各グループのノードの数

def find(x):
    while Group[x] != x:
        x=Group[x]
    return x

def Union(x,y):
    if find(x) != find(y):
        if Nodes[find(x)] < Nodes[find(y)]:
            
            Nodes[find(y)] += Nodes[find(x)]
            Nodes[find(x)] = 0
            Group[find(x)] = find(y)
            
        else:
            Nodes[find(x)] += Nodes[find(y)]
            Nodes[find(y)] = 0
            Group[find(y)] = find(x)

E2=[]

for x,y,z in E:
    if find(x)!=find(y):
        E2.append((x,y,z))
        Union(x,y)

EDGE=[[] for i in range(N+1)]

D=[0]*(N+1)

for x,y,z in E2:
    EDGE[x].append((y,z))
    EDGE[y].append((x,z))
    D[x]+=1
    D[y]+=1

for i in range(1,N+1):
    if D[i]==1:
        ROOT=i
        break

QUE=[ROOT] 
Parent=[-1]*(N+1)
Score=[-1]*(N+1)
Parent[ROOT]=N+1 # ROOTの親を定めておく.
TOP_SORT=[] # トポロジカルソート

while QUE: # トポロジカルソートと同時に親を見つける
    x=QUE.pop()
    TOP_SORT.append(x)
    for to,sc in EDGE[x]:
        if Parent[to]==-1:
            Score[to]=sc
            Parent[to]=x
            QUE.append(to)

Children=[1]*(N+1)

for x in TOP_SORT[1:][::-1]: #（自分を含む）子ノードの数を調べる
    Children[Parent[x]]+=Children[x]

ANS=0
for i in range(1,N+1):
    if i==ROOT:
        continue
    c=Children[i]
    ANS=ANS+c*(N-c)*pow(X,Score[i],mod)
    ANS%=mod

print(ANS)