Buggy python submission (verdict: Runtime Error):
import sys
import copy

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

V = []
E = []

for i in range(N):
    V.append(set())

for i in range(M):
    *l,  = map(int, input().split())
    V[l[0]-1].add(l[1]-1)
    V[l[1]-1].add(l[0]-1)
    E.append([l[0], l[1]])

count = 0


E_copy = copy.deepcopy(E)
V_copy = copy.deepcopy(V)

for i in range(M):
    e = [E[i][0], E[i][1]]

	V[e[0]].remove(e[1])
    V[e[1]].remove(e[0])
    
    #辺が存在しないノードがあるかをチェックする。
    for v in V:
        if len(v)==0:
            count = count + 1
            break
    
    E = copy.deepcopy(E_copy)
    V = copy.deepcopy(V_copy)
   
print(count)


Fixed submission:
import sys
import copy


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

V = []
E = []

for i in range(N):
    V.append(set())

seen = []
seen = [False] * N

count = 0
def dfs(node):
    global V
    global seen

    #注目ノードは訪問済みか?
    if seen[node]==True:
        return
    
    seen[node]=True

    for next_node in V[node]:
        dfs(next_node)
    return

for i in range(M):
    *l,  = map(int, input().split())
    V[l[0]-1].add(l[1]-1)
    V[l[1]-1].add(l[0]-1)
    E.append([l[0]-1, l[1]-1])



E_copy = copy.deepcopy(E)
V_copy = copy.deepcopy(V)
seen_copy = copy.deepcopy(seen)


for i in range(M):
    e = [E[i][0], E[i][1]]
    
    V[e[0]].remove(e[1])
    V[e[1]].remove(e[0])
    
    dfs(0)
    if (False in seen):
        count = count + 1
    seen = [False] * N
    V = copy.deepcopy(V_copy)
   
print(count)

Buggy python submission (verdict: Time Limit Exceeded):
import copy 
#深さ優先探索
def dfs(node, E_st_tmp):
      
    #辺の集合が存在しないとき
    if len(E_st_tmp) == 0:
        #全ての頂点を覗いた時
        if not (False in V_look):
            return 
        else:#辺の集合もないし、頂点もない。
            return 
    elif not (False in V_look): #辺の集合があっても全部見る時ある。
        return 

    #ここで探索する
    for i in range(V):
        E_st_tmp_copy   = copy.copy(E_st_tmp)

        if {node, i} in E_st_tmp_copy:
            V_look[i] = True
            E_st_tmp_copy.remove({node, i})
            dfs(i, E_st_tmp_copy)
    
    return

    
#連結かどうかのチェックする
V, E = map(int, input().split())

V_set = [v for v in range(V)]

E_set = []
for _ in range(E):
    a,b = map(int, input().split())
    E_set.append({a-1, b-1})

count = 0

for edge in E_set:
    E_set_cut = copy.copy(E_set)
    E_set_cut.remove(edge)
    #全ての頂点を覗いたか?
    V_look = [False] * V
    V_look[0] = True

    #深さ優先探索
    for v in range(V):
        E_set_copy  = copy.copy(E_set_cut)

        if {0, v} in E_set_copy:
            V_look[v] = True
            E_set_copy.remove({0, v})
            flg_t = dfs(v, E_set_copy)
    if (False in V_look):
        count += 1
        

print(count)



Fixed submission:
import sys
import copy


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

V = []
E = []

for i in range(N):
    V.append(set())

seen = []
seen = [False] * N

count = 0
def dfs(node):
    global V
    global seen

    #注目ノードは訪問済みか?
    if seen[node]==True:
        return
    
    seen[node]=True

    for next_node in V[node]:
        dfs(next_node)
    return

for i in range(M):
    *l,  = map(int, input().split())
    V[l[0]-1].add(l[1]-1)
    V[l[1]-1].add(l[0]-1)
    E.append([l[0]-1, l[1]-1])



E_copy = copy.deepcopy(E)
V_copy = copy.deepcopy(V)
seen_copy = copy.deepcopy(seen)


for i in range(M):
    e = [E[i][0], E[i][1]]
    
    V[e[0]].remove(e[1])
    V[e[1]].remove(e[0])
    
    dfs(0)
    if (False in seen):
        count = count + 1
    seen = [False] * N
    V = copy.deepcopy(V_copy)
   
print(count)