#include <stdio.h>

short main(){
    short n;
    scanf("%hi", &n);

    while(n--){
        short m, c;
        scanf("%hi %hi", &m, &c);
        short matriz[m][c];

        for(short i = 0; i<m; i++){
            for(short j = 0; j<c; j++){
                matriz[i][j]=0;
            }
        }

        for(short i = 0; i<c; i++){
            short cValor, hash;
            scanf("%hi", &cValor);

            hash = cValor % m;
            for(short i = 0; i<c; i++){
                if(matriz[hash][i] == 0){
                    matriz[hash][i] = cValor;
                    break;
                }
            }
        }

        for(short i = 0; i < m; i++){
            printf("%hi -> ", i);
            for(short j = 0; j<c; j++){
                if(matriz[i][j] == 0){
                    break;
                } else {
                    printf("%hi -> ", matriz[i][j]);
                }
            }
            printf("\\\n");
        }

        if(n) {
            printf("\n");
        }
    }
    return 0;
}