#include<set>

 #include<cmath>

 #include<queue>

 #include<vector>

 #include<cstdio>

 #include<cstring>

 #include<iostream>

 #include<algorithm>

 #define trav(u,i) for(int i=front[u];i;i=e[i].nxt)

 #define FOR(a,b,c) for(int a=(b);a<=(c);a++)

 using namespace std;

 typedef long long ll;

 const int N = 5e5+;

 ll read() {

     char c=getchar();

     ll f=,x=;

     while(!isdigit(c)) {

         if(c=='-') f=-; c=getchar();

     }

     while(isdigit(c))

         x=x*+c-'',c=getchar();

     return x*f;

 }

 ll C[N],tot;

 void upd(int x,ll v)

 {

     for(;x<=tot;x+=x&-x)

         C[x]=max(C[x],v);

 }

 ll query(int x)

 {

     ll res=;

     for(;x;x-=x&-x)

         res=max(res,C[x]);

     return res;

 }

 struct Node {

     int x,y,z;

     bool operator < (const Node& rhs) const{

         return x<rhs.x||(x==rhs.x&&y<rhs.y);

     }

 }ns[N];

 int r,c,n;

 int hash[N*];

 int main()

 {

     //freopen("in.in","r",stdin);

     //freopen("out.out","w",stdout);

     r=read(),c=read(),n=read();

     FOR(i,,n) {

         ns[i].x=read(),ns[i].y=read(),ns[i].z=read();

         hash[++tot]=ns[i].x,hash[++tot]=ns[i].y;

     }

     sort(hash+,hash+tot+);

     tot=unique(hash+,hash+tot+)-hash-;

     FOR(i,,n)

         ns[i].y=lower_bound(hash+,hash+tot+,ns[i].y)-hash;

     sort(ns+,ns+n+);

     ll ans=;

     FOR(i,,n) {

         ll x=query(ns[i].y)+ns[i].z;

         ans=max(ans,x);

         upd(ns[i].y,x);

     }

     printf("%d",ans);

     return ;

 }