#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;
const int K = 1e3 + 10;
int o2[K], n2[K], weight[K];
const int M = 25, N = 85;
int dp[M][N];
int main()
{
int m, n, k;
scanf("%d%d%d", &m, &n, &k);
for(int i = 1; i <= k; i++)
{
scanf("%d%d%d", &o2[i], &n2[i], &weight[i]);
}
memset(dp, 0x3f, sizeof dp);
dp[0][0] = 0;
for(int i = 1; i <= k; i++)
{
for(int j = m; j >= 0; j--)
{
for(int u = n; u >= 0; u--)
{
dp[j][u] = min(dp[j][u], dp[max(0, j - o2[i])][max(0, u - n2[i])] + weight[i]);
}
}
}
printf("%d\n", dp[m][n]);
}