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: Runtime Error)

#include <bits/stdc++.h>
using namespace std;
using pii=pair<int,int>;
using ll=long long;
using pll=pair<ll,ll>;

#define fi first
#define se second
#define pb push_back
#define rep(i,n) for(int i=0; i<(int)(n); i++)
#define MOD 1000000007

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }

int main() {
	int N,M;
	cin >> N >> M;
	vector<int> P(M),Y(M);
	vector<vector<pii>> v(M, vector<pii>());
	rep(i,M) {
		cin >> P[i] >> Y[i];
		P[i]--;
		v[P[i]].pb(pii(Y[i],i));
	}
	rep(i,M) {
		sort(v[i].begin(), v[i].end());
	}
	vector<pii> t(M);
	rep(i,M) {
		for(int j=0; j<v[i].size(); j++) {
			t[v[P[i]][j].se] = pii(P[i]+1, j+1);
			//cout << setfill('0') << right << setw(6) << P[i]+1 << setfill('0') << right << setw(6) << j+1 << endl;
		}
	}
	rep(i,M) {
			cout << setfill('0') << right << setw(6) << t[i].fi << setfill('0') << right << setw(6) << t[i].se << endl;
	}


  return 0;
}