#include <bits/stdc++.h>
using namespace::std;
set <pair<int,int>> s[100005];
long long n,m,k,i,j,a[100005],x[100005],y[100005],r[100005],ans;
long long dodaj(int p,int l,int d){
long long ans,a,b;
ans=d-l+1;
set<pair<int,int>>::iterator it;
while(true){
it=s[p].lower_bound({l,d});
if(it==s[p].end()) break;
if((*it).second<=d) {ans-=(*it).second-(*it).first+1; s[p].erase(it);}
else break;
}
it=s[p].lower_bound({l,d});
a=l;
b=d;
if(it!=s[p].end() && d+1>=(*it).first){
b=(*it).second;
ans-=d+1-(*it).first;
s[p].erase(it);
}
it=s[p].lower_bound({l,d});
if(it!=s[p].begin()){
it--;
if((*it).second+1>=l){
a=(*it).first;
ans-=(*it).second+1-l;
s[p].erase(it);
}
}
s[p].insert({a,b});
return ans;
}
int main(){
std::ios_base::sync_with_stdio(0);
cin>>n>>m>>k;
for(i=0;i<k;i++){
cin>>x[i]>>y[i]>>r[i];
}
ans=n*m*k;
for(i=k-1;i>=0;i--){
a[i]=0;
for(j=y[i]-r[i];j<=y[i]+r[i];j++){
long long d;
d=sqrt(r[i]*r[i]-(j-y[i])*(j-y[i]));
if(d*d>r[i]*r[i]-(j-y[i])*(j-y[i])) d--;
a[i]+=dodaj(j,x[i]-d,x[i]+d);
}
ans-=(i+1)*a[i];
}
cout<<ans<<endl;
return 0;
}
