m, n = map(int, input().split())
k = int(input())
max_weight = 0
gas = []
max_c = 0
for _ in range(k):
a, b, c = map(int, input().split())
gas.append([a, b, c])
max_c += c
dp = [[max_c] * (n+1) for _ in range(m+1)] # 满足i, j下的最小重量
dp[0][0] = 0
for a, b, c in gas:
for i in range(m, -1, -1):
for j in range(n, -1, -1):
dp[i][j] = min(dp[i][j], dp[max(0,i-a)][max(0,j-b)]+c)
print(dp[m][n])