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 (GCC 5.4.1) (judge verdict: Accepted)

#include<stdio.h>
#include<stdlib.h>
#include<math.h>
#include<string.h>
typedef long long ll;
typedef long double ld;
#define rep(i,l,r)for(ll i=(l);i<(r);i++)
#define repp(i,l,r,k)for(ll i=(l);i<(r);i+=(k))
#define INF (1LL<<60)
#define MOD1 1000000007
#define MAX_N (1 << 17)


void swap(ll *a, ll *b){ll c;c=*b;*b=*a;*a=c;}
ll max2(ll a,ll b){return a>=b?a:b;}
ll min2(ll a,ll b){return a>=b?b:a;}
ll minn(ll n, ll a[n]){ll b=INF;rep(i,0,n) b=min2(b,a[i]);return b;}
ll maxn(ll n, ll a[n]){ll b=-INF;rep(i,0,n) b=max2(b,a[i]);return b;}
ll ABS(ll a){return a>=0?a:(-a);}
ll POW(ll a, ll b){ll c=1;rep(i,0,b) c*=a;return c;}
ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
ll lcm(ll a,ll b){return a/gcd(a,b)*b;}
int upll(const void*a, const void*b){return*(ll*)a<*(ll*)b?-1:*(ll*)a>*(ll*)b?1:0;}
int downll(const void*a, const void*b){return*(ll*)a<*(ll*)b?1:*(ll*)a>*(ll*)b?-1:0;}
void sortup(ll*a,int n){qsort(a,n,sizeof(ll),upll);}
void sortdown(ll*a,int n){qsort(a,n,sizeof(ll),downll);}

typedef struct{
    ll a;
    ll b;
    ll c;
    ll d;
}frequent;

int cmp( const void *p, const void *q ) {
    if( ((frequent*)p)->a == ((frequent*)q)->a ) return ((frequent*)p)->b - ((frequent*)q)->b;
    return ((frequent*)p)->a - ((frequent*)q)->a;
}
int cmp1( const void *p, const void *q ) {
    // if( ((frequent*)p)->a == ((frequent*)q)->a ) return ((frequent*)p)->b - ((frequent*)q)->b;
    return ((frequent*)p)->c - ((frequent*)q)->c;
}

int main(void){
    // char ;
    ll n,m;
    scanf("%lld%lld",&n,&m);
    frequent x[m];
    rep(i,0,m){
        scanf("%lld%lld",&x[i].a,&x[i].b);
        x[i].c=i;
    }
    qsort(x,m,sizeof(frequent),cmp);
    ll y=1;
    x[0].d=1;
    rep(i,1,m){
        if(x[i].a==x[i-1].a){
            y++;
        }else{
            y=1;
        }
        x[i].d=y;
    }
    qsort(x,m,sizeof(frequent),cmp1);
    rep(i,0,m){
        printf("%06lld%06lld\n",x[i].a,x[i].d);
    }
    // printf("\n");
    return 0;
}