#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;

const int K = 1010, N = 25, M = 85;
int f[N][M];

int main()
{
 memset(f, 0x3f, sizeof f);
 f[0][0] = 0;
 int k;
 int vo, vn;
 cin >> vo >> vn;
 cin >> k;
 for (int i = 0; i < k; i ++){
     int o, n, w;
     scanf("%d%d%d", &o, &n, &w);
     for (int jo = vo; jo >= 0; jo --)
        for (int jn = vn; jn >= 0; jn --)
            f[jo][jn] = min(f[jo][jn], f[max(0, jo - o)][max(0, jn - n)] + w);
 }

 cout << f[vo][vn] << endl;

 return 0;
 }