#include < iostream >
using   namespace  std;

int  vn,vm,n;
int  v,w,c;
int  f[ 22 ][ 82 ];
int  main()
{
    scanf( " %d%d%d " , & vn, & vm, & n);
    memset(f, 0x7F , sizeof (f));
    f[ 0 ][ 0 ] = 0 ;
     for ( int  i = 1 ;i <= n; ++ i){
        scanf( " %d%d%d " , & v, & w, & c);
         for ( int  j = vn;j >= 0 ; -- j)
             for ( int  k = vm;k >= 0 ; -- k)  if (f[j][k] < 0xFFFFFFF ){
                 int  va = j + v;  if (va > vn) va = vn;
                 int  vb = k + w;  if (vb > vm) vb = vm;
                 if (f[va][vb] > f[j][k] + c)
                    f[va][vb] = f[j][k] + c;
            }
    }
    printf( " %d\n " ,f[vn][vm]);
     return   0 ;
}