#include <algorithm>
#include <iostream>
#include <cstring>
#include <cstdio>
#include <cmath>
#include <queue>
#define LL long long
#define Max(x, y) (x >= y ? x : y)
#define Min(x, y) (x <= y ? x : y)
#define MM(x, y) memset(x, y, sizeof(x))
#define F(i, x, y) for(register int i=x; i<=y; i++)
#define R(i, x, y) for(register int i=x; i>=y; i--)

using namespace std;

inline void in(int &x)
{
    static int ch; static bool flag;
    for(flag=false, ch=getchar(); ch<'0'||ch>'9'; ch=getchar()) flag |= ch=='-';
    for(x=0; isdigit(ch); ch=getchar()) x = (x<<1) + (x<<3) + ch - '0';
    x = flag ? -x : x;
}

int t, a, n;
struct node{
	int v, O, N;
}th[1005];
int f[30][90];

inline int work()
{
    freopen("ple.in","r",stdin); freopen("ple.out","w",stdout);
	in(t); in(a); in(n);
	F(i, 1, n) in(th[i].O), in(th[i].N), in(th[i].v);
	MM(f, 127/3); f[0][0] = 0;
	F(i, 1, n) {
		R(j, t, 0) R(k, a, 0) {
			int k1 = j + th[i].O, k2 = k + th[i].N;
			if (k1 > t) k1 = t; if (k2 > a) k2 = a;
			f[k1][k2] = Min(f[k1][k2], f[j][k]+th[i].v);
		}
	}
	printf("%d\n", f[t][a]);
	return 0;
}

int TAT = work();
int main() {;}