#include<bits/stdc++.h>
#define ll long long
#define ull unsigned ll
#define uint unsigned
#define pii pair<int,int>
#define pll pair<ll,ll>
#define IT iterator
#define PB push_back
#define fi first
#define se second
#define For(i,j,k) for (int i=(int)(j);i<=(int)(k);i++)
#define Rep(i,j,k) for (int i=(int)(j);i>=(int)(k);i--)
#define CLR(a,v) memset(a,v,sizeof(a));
#define CPY(a,b) memcpy(a,b,sizeof(a));
#define debug puts("wzpakking")
#define y1 ysghysgsygsh 
using namespace std;
int n,m,k,x[10],y[10],z[10];
int s[65];
bool check(int d){
    memset(s,0,sizeof(s));
    For(i,1,n) For(j,1,m){
        int flg=0;
        For(p,1,k)
            if (abs(x[p]-i)+abs(y[p]-j)<=d)
                flg|=1<<(p-1);
        ++s[flg];
    }
    //cout<<d<<' ';
    //For(i,0,(1<<k)-1) cout<<s[i]<<' '
    For(i,0,(1<<k)-1){
        int s1=0,s2=0;
        For(j,0,(1<<k)-1) if ((i&j)==j) s1+=s[j];
        For(j,0,k-1) if (i&(1<<j)) s2+=z[j+1];
        if (s1>s2) return 0;
    }
    return 1;
}
void solve(){
    scanf("%d%d%d",&n,&m,&k);
    For(i,1,k) scanf("%d%d%d",&x[i],&y[i],&z[i]);
    int l=0,r=1e9,ans=-1;
    while (l<=r){
        int mid=(l+r)/2;
        if (check(mid))
            ans=mid,r=mid-1;
        else l=mid+1;
    }
    cout<<ans<<endl;
}
int main(){
    int T;
    scanf("%d",&T);
    while (T--) solve();
}