n, m = map(int, input().split())
score={i: 0 for i in range(1, m + 1)}
for _ in range(n):
ans, *arr = input().rstrip().split()
i=0
while i<len(arr)-1:
if (arr[i + 1]).isdigit():i+=1
elif arr[i+1].strip()==ans.strip():
score[int(arr[i])] += 1
i+=2
break
else: i+=2
max_score = max(score.values())
print(" ".join(str(i) for i in range(1, m + 1) if score[i]==max_score))
print("\n".join(f"{i} {score[i]}" for i in range(1, m + 1)))