//Δ_1007
#include<iostream>
#include<cstdio>
#include<fstream>
#include<algorithm>
#include<vector>
#include<map>
#include<set>
#include<queue>
#include<bitset>
#include<cmath>
#include<cstring>
#include<cstdlib>
using namespace std;
typedef long long LL;
typedef double DB;
const int N = 1111;
const int inf = 1e9;
struct edge{
    int pr;
    int to;
    int cap;
}e[111111];
int tot=1,la[N];
void clr(){
    tot=1;
    memset(la,0,sizeof(la));
}
void adde(int x,int y,int z){
    e[++tot].pr=la[x];
    la[x]=tot;
    e[tot].to=y;
    e[tot].cap=z;
}
void addf(int x,int y,int z=inf){
    adde(x,y,z);
    adde(y,x,0);
}
int d[N];
int bfs(int s,int t){
    queue<int> Q;
    int i,x,y;
    memset(d,0,sizeof(d));
    d[s]=1;
    Q.push(s);
    while(!Q.empty()){
        x=Q.front();
        Q.pop();
        for(i=la[x];i;i=e[i].pr){
            if(!e[i].cap)
                continue;
            y=e[i].to;
            if(!d[y]){
                d[y]=d[x]+1;
                Q.push(y);
            }
        }
    }
    return d[t];
}
int dfs(int s,int t,int f){
    if(s==t)
        return f;
    int i,x,y,r=0;
    for(i=la[s];i;i=e[i].pr){
        if(!e[i].cap||!f)
            continue;
        y=e[i].to;
        if(d[y]!=d[s]+1)
            continue;
        x=dfs(y,t,min(f,e[i].cap));
        if(x){
            f-=x;
            r+=x;
            e[i].cap-=x;
            e[i^1].cap+=x;
        }
    }
    if(!r)
        d[s]=0;
    return r;
}
int maxflow(int s,int t){
    int x,r=0;
    while(bfs(s,t)){
        x=dfs(s,t,inf);
        if(x)
            r+=x;
        else
            break;
    }
    return r;
}
int ab(int x){
    if(x<0)
        return -x;
    return x;
}
int n,m,k,x[N],y[N],z[N],dis[N][N][7],cnt[1<<7];
int solve(int w){
    int i,j,o,x,s,t;
    memset(cnt,0,sizeof(cnt));
    for(i=1;i<=n;i=i+1){
        for(j=1;j<=m;j=j+1){
            x=0;
            for(o=0;o<k;o=o+1)
                if(dis[i][j][o]<=w)
                    x|=(1<<o);
            if(!x)
                return 0;
            cnt[x]++;
        }
    }
    clr();
    s=1,t=2;
    for(o=0;o<k;o=o+1){
        addf(s,o+11,z[o]);
        for(i=0;i<(1<<k);i=i+1)
            if(i&(1<<o))
                addf(o+11,i+111);
    }
    for(i=0;i<(1<<k);i=i+1)
        addf(i+111,t,cnt[i]);
    return (maxflow(s,t)==(n*m));
}
int main()
{
    int T,i,j,o,s,l,r,w;
    cin>>T;
    while(T--){
        cin>>n>>m>>k;
        s=0;
        for(o=0;o<k;o=o+1)
            cin>>x[o]>>y[o]>>z[o],s+=z[o];
        if(s<n*m){
            cout<<-1<<endl;
            continue;
        }
        for(o=0;o<k;o=o+1)
            for(i=1;i<=n;i=i+1)
                for(j=1;j<=m;j=j+1)
                    dis[i][j][o]=ab(i-x[o])+ab(j-y[o]);
        l=0,r=n+m;
        while(l<r){
            w=(l+r)/2;
            if(solve(w))
                r=w;
            else
                l=w+1;
        }
        cout<<l<<endl;
    }
    return 0;
}