import core.bitop;
import std.algorithm;
import std.ascii;
import std.bigint;
import std.conv;
import std.functional;
import std.math;
import std.numeric;
import std.range;
import std.stdio;
import std.string;
import std.random;
import std.typecons;
import std.container;

alias sread = () => readln.chomp();
long bignum = 1_000_000_007;
alias Prefecture = Tuple!(long, "ward", long, "established", long, "number");

T lread(T = long)()
{
    return readln.chomp.to!T();
}

T[] aryread(T = long)()
{
    return readln.split.to!(T[])();
}

void scan(TList...)(ref TList Args)
{
    auto line = readln.split();
    foreach (i, T; TList)
    {
        T val = line[i].to!(T);
        Args[i] = val;
    }
}

void main()
{
    long n, m;
    scan(n, m);
    auto id = new Prefecture[](m);
    foreach (i; 0 .. m)
    {
        long ward, established;
        scan(ward, established);
        id[i] = Prefecture(ward, established, i);
    }
    id.sort!"a.ward == b.ward ? a.established < b.established : a.ward < b.ward"();
    long count, corrent = id[0].ward;
    foreach (ref e; id)
    {
        if (corrent == e.ward)
        {
            e.established = ++count;
        }
        else
        {
            count = 0;
            e.established = ++count;
        }
    }
    id.sort!"a.number < b.number"();
    foreach (e; id)
    {
        writef("%06s%06s", e.ward, e.established);
        writeln();
    }
}