Problem:
Score: 300 points

Problem Statement

In Republic of Atcoder, there are N prefectures, and a total of M cities that belong to those prefectures.

City i is established in year Y_i and belongs to Prefecture P_i.

You can assume that there are no multiple cities that are established in the same year.

It is decided to allocate a 12-digit ID number to each city.

If City i is the x-th established city among the cities that belong to Prefecture i, the first six digits of the ID number of City i is P_i, and the last six digits of the ID number is x.

Here, if P_i or x (or both) has less than six digits, zeros are added to the left until it has six digits.

Find the ID numbers for all the cities.

Note that there can be a prefecture with no cities.

Constraints

1 \leq N \leq 10^5

1 \leq M \leq 10^5

1 \leq P_i \leq N

1 \leq Y_i \leq 10^9

Y_i are all different.

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N M
P_1 Y_1
:
P_M Y_M

Output

Print the ID numbers for all the cities, in ascending order of indices (City 1, City 2, ...).

Sample Input 1

2 3
1 32
2 63
1 12

Sample Output 1

000001000002
000002000001
000001000001

As City 1 is the second established city among the cities that belong to Prefecture 1, its ID number is 000001000002.

As City 2 is the first established city among the cities that belong to Prefecture 2, its ID number is 000002000001.

As City 3 is the first established city among the cities that belong to Prefecture 1, its ID number is 000001000001.

Sample Input 2

2 3
2 55
2 77
2 99

Sample Output 2

000002000001
000002000002
000002000003

Solution in C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <bits/stdc++.h>
using namespace std;
#define FOR(i,a,b) for (int i = a; i < b; i++)
#define REP(i,b) FOR(i,0,b)
#define RFOR(i,a,b) for (int i = a-1; i >= b; i--)
#define RREP(i,a) RFOR(i,a,0)
#define REPALL(i,v) for (int i = 0; i < v.size(); i++)
#define SORT(v) sort(v.begin(), v.end())
#define FIND(v,n) find(v.begin(), v.end(), n)
#define MIN_ELEMENT(v) min_element(v.begin(), v.end())
#define MAX_ELEMENT(v) max_element(v.begin(), v.end())
#define COUNT(v,n) count(v.begin(), v.end(), n);
typedef long long ll;
typedef unsigned long long ull;
const int INF = 1e7;
const ll MOD = 1e9 + 7;

ll p[111111], y[111111];
vector<ll> v[111111];

ll getid(int i)
{
    vector<ll> t = v[p[i]];
    ll l = 0, r = t.size();
    ll mid = (l + r) / 2, val;
    ll k = t.size();
    REP(j, k) {
        val = t[mid] - y[i];
        if (val == 0) {
            break;
        } else if (val > 0) {
            r = mid;
        } else {
            l = mid;
        }
        mid = (l + r) / 2;
    }
    return mid + 1;
}

int main()
{
    int n, m;
    cin>>n>>m;

    REP(i,m) {
        cin>>p[i]>>y[i];
        v[p[i]].push_back(y[i]);
    }

    REP(i,n) {
        SORT(v[i]);
    }

    REP(i,m) {
        printf("%06d%06d\n", p[i], getid(i));
    }

    return 0;
}