#include<bits/stdc++.h>
#define rep(i, a, b) for(int i=(a) ; i<=(b) ; ++i)
#define Task ""
using namespace std;
const int inf=1000000000;
struct data {
int p, val, t;
bool operator < (const data &X) const {
return t<X.t;
}
} e[105];
int dp[105][2001], n, m, k, maxt;
void MAX(int &a, int b) {
a=max(a, b);
}
int main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
//freopen(Task".inp", "r", stdin);
//freopen(Task".out", "w", stdout);
cin >> n >> k >> m;
rep(i, 1, m) {
int pos, val, t;
cin >> pos >> val >> t;
e[i]={pos, val, t};
}
sort(e+1, e+m+1);
maxt=e[m].t;
rep(i, 0, m)
rep(j, 0, maxt) dp[i][j]=-inf;
e[0]={k, 0, 0};
dp[0][0]=0;
rep(i, 1, m)
rep(t, 0, maxt)
rep(j, 0, i-1) {
int dis=abs(e[i].p-e[j].p);
if(t<dis||dp[j][t-dis]==-inf) continue;
if(t>=e[i].t) MAX(dp[i][t], dp[j][t-dis]);
else MAX(dp[i][t], dp[j][t-dis]+e[i].val);
}
int ans=0;
rep(i, 1, m)
rep(j, 0, maxt)
MAX(ans, dp[i][j]);
cout << ans;
return 0;
}
