题解 | #合并表记录#

import sys

def statistics(lines):
    if lines<1 or lines > 500:
        raise Exception('键值对个数超限制！')
        return
    else:
        result = dict()
        for line in range(lines):
            # 获得每行的key和value的值
            key, value = sys.stdin.readline().strip().split(' ')
            key = int(key)
            value = int(value)
            if key in result.keys():
                result[key] = result[key] + value
            else:
                result[key] = value
        # 排序
        sorted_keys = sorted(result.keys())
        # 输出
        for key in sorted_keys:
            print("{} {}".format(key, result[key]))
        

if __name__ == '__main__':
            # 或取行数
    lines = int(sys.stdin.readline().strip())
    statistics(lines)