n, a, b = list(map(int, input().split()))
s = input()
ans = 0
while len(s) > 0:
    l = 0
    r = len(s) // 2
    m = 0
    ok = 0
    while l <= r:
        m = (l + r) // 2
        if s[len(s) - m::] in s[:len(s) - m]:
            ok = m
            l = m + 1
        else:
            r = m - 1
    if ok == 0:
        ans += a
        s = s[:-1]
    else:
        ans += min(ok * a, b)
        s = s[:-ok]
print(ans)