def max_profit(holidays, teams, profit):
    global maximum_sum

    for team in teams:
        for i in range(days_num - team[0] + 1):
            match = True
            new_days = list(holidays)
            for j in range(team[0]):
                if new_days[j + i] > 0:
                    new_days[j + i] = new_days[j + i] - 1
                    match = True
                else:
                    match = False
                    break

            if match:
                new_teams = list(teams)
                new_teams.remove(team)
                max_profit(new_days, new_teams, profit + team[1])

    same_nuly = True

    for d in holidays:
        if d != 0:
            same_nuly = False

    if same_nuly:
        maximum_sum = max(maximum_sum, profit)


maximum_sum = 0
line = input()

days_num = int(line.split()[0])
teams_num = int(line.split()[1])

line = input()

days = [int(x) for x in line.split()]
teams = []

for i in range(teams_num):
    line = input()
    teams.append([int(x) for x in line.split()])

# print(teams)
# print(days)

# print(max(5, 6))
max_profit(days, teams, 0)
# print(teams[2])
print(maximum_sum)