#include <bits/stdc++.h>
#define sz(x) int(x.size())
#define in(x) freopen(x, "r", stdin)
#define out(x) freopen(x, "w", stdout)
#define N 100500
#define oo ll(1e16)
#define ft first
#define sd second
#define pb push_back
#define ppb pop_back
#define el '\n'
#define elf endl
#define base ll(1e9 + 7)
using namespace std;
typedef long long ll;
typedef long double ld;
ll n, m, k, a[N], b[N], r[N], ans;
ll sqr(ll x) { return x * x; }
int main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n >> m >> k;
for (int i = 0; i < k; i++)
cin >> a[i] >> b[i] >> r[i], a[i]--, b[i]--;
for (int i = 0; i < n; i++)
for (int j = 0; j < m; j++) {
int p = -1;
for (int l = 0; l < k; l++)
if (sqr(abs(i - a[l])) + sqr(abs(j - b[l])) <= sqr(r[l]))
p = l;
ans += k - 1 - p;
}
cout << ans;
}
