Buggy python submission (verdict: Time Limit Exceeded):
class UnionFind():
    def __init__(self, n):
        self.n = n
        self.parents = [-1] * n

    def find(self, x):
        if self.parents[x] < 0:
            return x
        else:
            self.parents[x] = self.find(self.parents[x])
            return self.parents[x]

    def union(self, x, y):
        x = self.find(x)
        y = self.find(y)

        if x == y:
            return

        if self.parents[x] > self.parents[y]:
            x, y = y, x

        self.parents[x] += self.parents[y]
        self.parents[y] = x

    def size(self, x):
        return -self.parents[self.find(x)]

    def same(self, x, y):
        return self.find(x) == self.find(y)

    def members(self, x):
        root = self.find(x)
        return [i for i in range(self.n) if self.find(i) == root]

    def roots(self):
        return [i for i, x in enumerate(self.parents) if x < 0]

    def group_count(self):
        return len(self.roots())

    def all_group_members(self):
        return {r: self.members(r) for r in self.roots()}

    def __str__(self):
        return '\n'.join('{}: {}'.format(r, self.members(r)) for r in self.roots())


N, M = map(int, input().split())
AB = []
for _ in range(M):
    a, b = map(int, input().split())
    a -= 1
    b -= 1
    AB.append((a, b))
AB = AB[::-1]
uf = UnionFind(N)
ans = [0]
comb = N * (N - 1) // 2
for a, b in AB:
    uf.union(a, b)
    cnt = 0
    # print(uf.all_group_members())
    for v in uf.all_group_members().values():
        if 1 < len(v):
            d = len(v)
            cnt += d * (d - 1) // 2
    ans.append(cnt)
ans = ans[:-1][::-1]
for x in ans:
    print(comb - x)

Fixed submission:
class UnionFind():
    def __init__(self, n):
        self.n = n
        self.parents = [-1] * n

    def find(self, x):
        if self.parents[x] < 0:
            return x
        else:
            self.parents[x] = self.find(self.parents[x])
            return self.parents[x]

    def union(self, x, y):
        x = self.find(x)
        y = self.find(y)

        if x == y:
            return 0

        if self.parents[x] > self.parents[y]:
            x, y = y, x

        a = self.parents[x]
        b = self.parents[y]

        self.parents[x] += self.parents[y]
        self.parents[y] = x

        return (a * b)

    def size(self, x):
        return -self.parents[self.find(x)]

    def same(self, x, y):
        return self.find(x) == self.find(y)

    def members(self, x):
        root = self.find(x)
        return [i for i in range(self.n) if self.find(i) == root]

    def roots(self):
        return [i for i, x in enumerate(self.parents) if x < 0]

    def group_count(self):
        return len(self.roots())

    def all_group_members(self):
        return {r: self.members(r) for r in self.roots()}

    def __str__(self):
        return '\n'.join('{}: {}'.format(r, self.members(r)) for r in self.roots())


N, M = map(int, input().split())
AB = []
for _ in range(M):
    a, b = map(int, input().split())
    a -= 1
    b -= 1
    AB.append((a, b))
AB = AB[::-1]
uf = UnionFind(N)
ans = []
comb = N * (N - 1) // 2
tmp = comb
for a, b in AB:
    tmp -= uf.union(a, b)
    # print(cnt)
    ans.append(tmp)
# print(ans)
ans = ans[:-1][::-1]
# print(ans)
for x in ans:
    print(x)
print(comb)

Buggy python submission (verdict: Time Limit Exceeded):
class UnionFind():
    def __init__(self, n):
        self.n = n
        self.parents = [-1] * n

    def find(self, x):
        if self.parents[x] < 0:
            return x
        else:
            self.parents[x] = self.find(self.parents[x])
            return self.parents[x]

    def union(self, x, y):
        x = self.find(x)
        y = self.find(y)

        if x == y:
            return

        if self.parents[x] > self.parents[y]:
            x, y = y, x

        self.parents[x] += self.parents[y]
        self.parents[y] = x

    def size(self, x):
        return -self.parents[self.find(x)]

    def same(self, x, y):
        return self.find(x) == self.find(y)

    def members(self, x):
        root = self.find(x)
        return [i for i in range(self.n) if self.find(i) == root]

    def roots(self):
        return [i for i, x in enumerate(self.parents) if x < 0]

    def group_count(self):
        return len(self.roots())

    def all_group_members(self):
        return {r: self.members(r) for r in self.roots()}

    def __str__(self):
        return '\n'.join('{}: {}'.format(r, self.members(r)) for r in self.roots())


N, M = map(int, input().split())
AB = []
for _ in range(M):
    a, b = map(int, input().split())
    a -= 1
    b -= 1
    AB.append((a, b))
AB = AB[::-1]
uf = UnionFind(N)
ans = [0]
comb = N * (N - 1) // 2
for a, b in AB:
    uf.union(a, b)
    cnt = 0
    # print(uf.all_group_members())
    for v in uf.all_group_members().values():
        if 1 < len(v):
            d = len(v)
            cnt += d * (d - 1) // 2
    ans.append(cnt)
ans = ans[:-1][::-1]
for x in ans:
    print(comb - x)

Fixed submission:
class UnionFind():
    def __init__(self, n):
        self.n = n
        self.parents = [-1] * n

    def find(self, x):
        if self.parents[x] < 0:
            return x
        else:
            self.parents[x] = self.find(self.parents[x])
            return self.parents[x]

    def union(self, x, y):
        x = self.find(x)
        y = self.find(y)

        if x == y:
            return 0

        if self.parents[x] > self.parents[y]:
            x, y = y, x

        a = self.parents[x]
        b = self.parents[y]

        self.parents[x] += self.parents[y]
        self.parents[y] = x

        return (a * b)

    def size(self, x):
        return -self.parents[self.find(x)]

    def same(self, x, y):
        return self.find(x) == self.find(y)

    def members(self, x):
        root = self.find(x)
        return [i for i in range(self.n) if self.find(i) == root]

    def roots(self):
        return [i for i, x in enumerate(self.parents) if x < 0]

    def group_count(self):
        return len(self.roots())

    def all_group_members(self):
        return {r: self.members(r) for r in self.roots()}

    def __str__(self):
        return '\n'.join('{}: {}'.format(r, self.members(r)) for r in self.roots())


N, M = map(int, input().split())
AB = []
for _ in range(M):
    a, b = map(int, input().split())
    a -= 1
    b -= 1
    AB.append((a, b))
AB = AB[::-1]
uf = UnionFind(N)
ans = []
comb = N * (N - 1) // 2
tmp = comb
for a, b in AB:
    tmp -= uf.union(a, b)
    # print(cnt)
    ans.append(tmp)
# print(ans)
ans = ans[:-1][::-1]
# print(ans)
for x in ans:
    print(x)
print(comb)