#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 (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);
}
}
int n,m;
int t[4*MAXN];
pii lazy[4*MAXN];
void push(int nd,int l,int r){
if(lazy[nd].fi==-1 or l==r) return; //no assignment
if(lazy[nd].fi==0){
lazy[nd*2]=lazy[nd*2+1]=lazy[nd];
t[nd*2]=t[nd*2+1]=0;
lazy[nd].fi=-1;
return;
}
if(lazy[nd].se>lazy[nd*2].se){
lazy[nd*2]=lazy[nd];
t[nd*2]=(mid-l+1)*lazy[nd].fi;
}
else if(lazy[nd].se==lazy[nd*2].se){
if(lazy[nd].fi>lazy[nd*2].fi){
lazy[nd*2]=lazy[nd];
t[nd*2]=(mid-l+1)*lazy[nd].fi;
}
}
if(lazy[nd].se>lazy[nd*2+1].se){
lazy[nd*2+1]=lazy[nd];
t[nd*2+1]=(r-(mid+1)+1)*lazy[nd].fi;
}
else if(lazy[nd].se==lazy[nd*2+1].se){
if(lazy[nd].fi>lazy[nd*2+1].fi){
lazy[nd*2+1]=lazy[nd];
t[nd*2+1]=(r-(mid+1)+1)*lazy[nd].fi;
}
}
lazy[nd].fi=-1;
}
int cur;
void update(int ql,int qr,int val,int nd=1,int l=1,int r=m){
if(l>r or l>qr or r<ql) return;
push(nd,l,r);
if(ql<=l and r<=qr){
//cout<<"segt" sp l sp r sp ql sp qr sp val<<endl;
t[nd]=val*(r-l+1);
lazy[nd]={val,cur};
return;
}
update(ql,qr,val,nd*2,l,mid);
update(ql,qr,val,nd*2+1,mid+1,r);
t[nd]=t[nd*2]+t[nd*2+1];
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
calc();
cin>>n>>m;
int k;
cin>>k;
vi x(k+1),y(k+1),r(k+1);
FORE(i,1,k+1){
cin>>y[i]>>x[i]>>r[i];
}
int ans=n*m*k;
FORE(yy,1,n+1){ //her satır için
update(1,m,0);
cur=yy;
FORE(i,1,k+1){ //tüm kları gez
int deg=r[i]*r[i]-abs(yy-y[i])*abs(yy-y[i]);
auto c=upper_bound(all(kare),deg)-1-kare.begin();
//cout<<"here" sp yy sp i sp x[i]-c sp x[i]+c<<endl;
if(c>=0){
update(x[i]-c,x[i]+c,i);
}
}
ans-=t[1];
}
cout<<ans<<endl;
}
