# len of LC
n = int(input().strip())

# owners
s = input()

# number of pizzo types
k = int(input().strip())

# pizzo categories
cc = {}
# the best category
best = "!"
for i in range(k):
    c, v_str = input().strip().split()
    v = int(v_str)
    cc[c] = v
    if best == "!" or v > cc[best]:
        best = c

# the prime
p = 2
while(n % p != 0):
    p += 1

def log(x):
    power = 0
    prod = 1
    while(prod < x):
        power += 1
        prod *= p
    return power

def solve(step, offset):
    count = n // step
    pizzo = "?"
    for oi in range(offset, n, step):
        if s[oi] == pizzo or s[oi] == "?":
            continue
        elif s[oi] != "?" and pizzo == "?":
            pizzo = s[oi]
        else:
            pizzo = "#"
    if pizzo == "?":
        return count * cc[best] * (log(count) + 1)
    else:
        sumOfChildren = 0
        if step < n:
            stepNew = step * p
            for i in range(p):
                sumOfChildren += solve(stepNew, offset + i * step)
        if pizzo == "#":
            return sumOfChildren
        else:
            return max(sumOfChildren, count * cc[pizzo] * (log(count) + 1))

print(solve(1, 0))