#include<bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
#define int long long
//#define int double
typedef pair<int,int> pii;
typedef vector<pii> vii;
typedef vector<int> vi;
typedef vector<bool> vb;
#define FOR(i,a) for(int i=0;i<(a);i++)
#define FORE(i,a,b) for(int i=(a);i<(b);i++)
#define all(x) x.begin(),x.end()
#define fi first
#define se second
#define pb push_back
#define sp <<" "<<
#define cont(x) for(auto el:x) cout<<el<<' ';cout<<endl;
#define contp(x) for(auto el:x) cout<<el.fi<<'-'<<el.se<<' ';cout<<endl;
#define DEBUG(x) cout<<#x sp x<<endl;
#define carp(x,y) ((x%MOD)*(y%MOD))%MOD
#define topla(x,y) ((x%MOD)+(y%MOD))%MOD
#define mid (double)(l+r)/2
const int MAXN=1e5+5;
const int MOD=1e9+7;
const int INF=1e18;
vi kare;
void calc(){
FORE(i,0,MAXN){
kare.pb(i*i);
}
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
calc();
int n,m;
cin>>n>>m;
int k;
cin>>k;
vector<vi> grid(n+1, vi(m+1,k));
vi x(k+1),y(k+1),r(k+1);
FORE(i,1,k+1){
cin>>x[i]>>y[i]>>r[i];
}
vector<vb> used(n+1,vb(m+1,false));
for(int i=k;i>0;i--){
int say=0;
FORE(yy,y[i]-r[i],y[i]+r[i]+1){
int deg=r[i]*r[i]-abs(yy-y[i])*abs(yy-y[i]);
//DEBUG(deg);
//karesi degten küçük max degeri bul
auto c=upper_bound(all(kare),deg)-1-kare.begin();
//DEBUG(c);
FORE(xx,x[i]-c,x[i]+c+1){
if(!used[xx][yy]){
used[xx][yy]=true;
grid[xx][yy]=k-i;
say++;
}
}
}
}
int ans=0;
FORE(i,1,n+1){
FORE(j,1,m+1){
ans+=grid[i][j];
}
}
cout<<ans<<endl;
}
