n = int(input())
students = []
# 读取学生信息
for _ in range(n):
    student_id, score = map(int, input().split())
    students.append((student_id, score))
# 排序：先按成绩升序，成绩相同按学号升序
print(students)
students.sort(key=lambda x: (x[1], x[0]))
# 输出结果
for student in students:
    print("%d %d"%(student[0],student[1]))