玄关

#include<bits/stdc++.h>
using namespace std;
#define getchar getchar_unlocked
int n,m;
inline int read(){
    int a = 0;
    int sign = 1;char ch = getchar();
    while(ch < '0' || ch > '9'){
        if(ch == '-'){sign = -1;}
        ch = getchar();
    }
    while(ch >= '0' && ch <= '9'){a = 10*a + ch - '0';ch = getchar();}
    a *= sign;
    return a;
}
inline void write(int x){
    if(x < 0){putchar('-');x = -x;}
    if(x >= 10)write(x/10);
    putchar(x%10+'0');
}
int main(){
    ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    int t;t = read();
    // write(t);return 0;
    while(t--){
        n = read();m = read();
        priority_queue<int,vector<int>,greater<int>>a[500005];
        for(int i = 1;i <= m;i++){
            int u,v;u = read();v = read();
            a[u].push(v);
        }
        for(int i = 1;i <= n;i++){
            while(a[i].size()){
                write(a[i].top());putchar(' ');
                a[i].pop();
            }
            putchar('\n');
        }
    }
    return 0;
}