Buggy python submission (verdict: Time Limit Exceeded):
n, m, l = map(int, input().split())
def warshall_floyd(d):
    #d[i][j]: iからjへの最短距離
    for k in range(n):
        for i in range(n):
            for j in range(n):
                d[i][j] = min(d[i][j],d[i][k] + d[k][j])
    return d
inf = 10**12
d = [[inf for i in range(n)] for i in range(n)] 
#d[u][v] : 辺uvのコスト(存在しないときはinf)
for i in range(m):
    x,y,z = map(int,input().split())
    d[x-1][y-1] = z
    d[y-1][x-1] = z
for i in range(n):
    d[i][i] = 0 #自身のところに行くコストは０
dd = warshall_floyd(d)
ddd = [[inf for i in range(n)] for i in range(n)]
for i in range(n):
  for j in range(n):
    if dd[i][j] <= l:
      ddd[i][j] = 1
dddd = warshall_floyd(ddd)
q = int(input())
for i in range(q):
  s, t = map(int, input().split())
  if dddd[s-1][t-1] == inf:
    print(-1)
  else:
    print(dddd[s-1][t-1]-1)

Fixed submission:
from scipy.sparse.csgraph import floyd_warshall

n, m, l = map(int, input().split())
inf = 10**12
d = [[inf for i in range(n)] for i in range(n)] 
#d[u][v] : 辺uvのコスト(存在しないときはinf)
for i in range(m):
    x,y,z = map(int,input().split())
    d[x-1][y-1] = z
    d[y-1][x-1] = z
for i in range(n):
    d[i][i] = 0 #自身のところに行くコストは０
dd = floyd_warshall(d)
ddd = [[inf for i in range(n)] for i in range(n)]
for i in range(n):
  for j in range(n):
    if dd[i][j] <= l:
      ddd[i][j] = 1
dddd =floyd_warshall(ddd)
q = int(input())
for i in range(q):
  s, t = map(int, input().split())
  if dddd[s-1][t-1] == inf:
    print(-1)
  else:
    print(int(dddd[s-1][t-1]-1))

Buggy python submission (verdict: Runtime Error):
n, m, l = map(int, input().split())
def warshall_floyd(d):
    #d[i][j]: iからjへの最短距離
    for k in range(n):
        for i in range(n):
            for j in range(n):
                d[i][j] = min(d[i][j],d[i][k] + d[k][j])
    return d
inf = 10**12
d = [[inf for i in range(n)] for i in range(n)] 
#d[u][v] : 辺uvのコスト(存在しないときはinf)
for i in range(m):
    x,y,z = map(int,input().split())
    d[x-1][y-1] = z
    d[y-1][x-1] = z
for i in range(n):
    d[i][i] = 0 #自身のところに行くコストは０
dd = warshall_floyd(d)
ddd = [[inf for i in range(n)] for i in range(n)]
for i in range(n):
  for j in range(n):
    if dd[i][j] <= l:
      ddd[i][j] = 1
dddd = warshall_floyd(ddd)
q = int(input())
for i in range(q):
  s, t = map(int, input().split())
  if dddd[s][t] == inf:
    print(-1)
  else:
    print(dddd[s-1][t-1]-1)

Fixed submission:
from scipy.sparse.csgraph import floyd_warshall

n, m, l = map(int, input().split())
inf = 10**12
d = [[inf for i in range(n)] for i in range(n)] 
#d[u][v] : 辺uvのコスト(存在しないときはinf)
for i in range(m):
    x,y,z = map(int,input().split())
    d[x-1][y-1] = z
    d[y-1][x-1] = z
for i in range(n):
    d[i][i] = 0 #自身のところに行くコストは０
dd = floyd_warshall(d)
ddd = [[inf for i in range(n)] for i in range(n)]
for i in range(n):
  for j in range(n):
    if dd[i][j] <= l:
      ddd[i][j] = 1
dddd =floyd_warshall(ddd)
q = int(input())
for i in range(q):
  s, t = map(int, input().split())
  if dddd[s-1][t-1] == inf:
    print(-1)
  else:
    print(int(dddd[s-1][t-1]-1))

Buggy python submission (verdict: Runtime Error):
n, m, l = map(int, input().split())
def warshall_floyd(d):
    #d[i][j]: iからjへの最短距離
    for k in range(n):
        for i in range(n):
            for j in range(n):
                d[i][j] = min(d[i][j],d[i][k] + d[k][j])
    return d
inf = 10**12
d = [[inf for i in range(n)] for i in range(n)] 
#d[u][v] : 辺uvのコスト(存在しないときはinf)
for i in range(m):
    x,y,z = map(int,input().split())
    d[x-1][y-1] = z
    d[y-1][x-1] = z
for i in range(n):
    d[i][i] = 0 #自身のところに行くコストは０
dd = warshall_floyd(d)
ddd = [[inf for i in range(n)] for i in range(n)]
for i in range(n):
  for j in range(n):
    if dd[i][j] <= l:
      ddd[i][j] = 1
dddd = warshall_floyd(ddd)
q = int(input())
for i in range(q):
  s, t = map(int, input().split())
  if dddd[s][t] == inf:
    print(-1)
  else
    print(dddd[s-1][t-1]-1)

Fixed submission:
from scipy.sparse.csgraph import floyd_warshall

n, m, l = map(int, input().split())
inf = 10**12
d = [[inf for i in range(n)] for i in range(n)] 
#d[u][v] : 辺uvのコスト(存在しないときはinf)
for i in range(m):
    x,y,z = map(int,input().split())
    d[x-1][y-1] = z
    d[y-1][x-1] = z
for i in range(n):
    d[i][i] = 0 #自身のところに行くコストは０
dd = floyd_warshall(d)
ddd = [[inf for i in range(n)] for i in range(n)]
for i in range(n):
  for j in range(n):
    if dd[i][j] <= l:
      ddd[i][j] = 1
dddd =floyd_warshall(ddd)
q = int(input())
for i in range(q):
  s, t = map(int, input().split())
  if dddd[s-1][t-1] == inf:
    print(-1)
  else:
    print(int(dddd[s-1][t-1]-1))