#include <cstdio>
#include <cstring>
#include <iostream>
using namespace std;
int f[125][125];
int wo[1002];
int wn[1002];
int w[1002];
int O2,N2;
int n;
int min(int x,int y)
{
    if(x<y)return x;
    return y;
}
int main()
{
    freopen("ple.in","r",stdin);
    freopen("ple.out","w",stdout);
    scanf("%d%d",&O2,&N2);
    scanf("%d",&n);
    int i,j,k;
 
    for(i=1;i<=n;i++)
        scanf("%d%d%d",&wo[i],&wn[i],&w[i]);
 
    memset(f,127,sizeof(f));
    f[0][0]=0;
    for(i=1;i<=n;i++)
        for(j=O2;j>=0;j--)
            for(k=N2;k>=0;k--)
            {
                int J=j+wo[i];
                int K=k+wn[i];
                if(J>O2)J=O2;
                if(K>N2)K=N2;
                f[J][K]=min(f[J][K],f[j][k]+w[i]);
            }
 
    printf("%d",f[O2][N2]);
    return 0;
}