from math import gcd

def inverse(n, d, MOD):
    return n * pow(d, -1, MOD) % MOD

def func(now, diff, cnt):
    if diff == 0:
        if now%M == 0:
            return cnt
        else:
            return 0
    if diff < 0:
        diff = -diff
    else:
        now = (M-now)%M
    GCD = gcd(M, diff)
    if now%GCD != 0:
        return 0
    n = now//GCD
    m = M//GCD
    d = diff//GCD
    c = inverse(n, d, m)
    if cnt <= c:
        return 0
    else:
        return (cnt-c-1)//m+1

N, K, M = map(int, input().split())
B = list(map(int, input().split()))
C = list(map(int, input().split()))

ln, lc = 0, 0
rn, rc = -1, 0
cnt = 0
SUM = 0
for i in range(N):
    if K <= cnt+B[i]:
        diff = K-cnt
        SUM += C[i]*diff
        rn, rc = i, diff-1
        break
    else:
        SUM += C[i]*B[i]
        cnt += B[i]
        rn, rc = i, B[i]-1

ans = 0
while rn < N:
    cnt1, cnt2 = B[ln]-lc, B[rn]-rc
    if cnt1 < cnt2:
        ans += func(SUM, C[rn]-C[ln], cnt1)
        SUM += (C[rn]-C[ln])*cnt1
        ln += 1
        lc = 0
        rc += cnt1
    elif cnt1 > cnt2:
        ans += func(SUM, C[rn]-C[ln], cnt2)
        SUM += (C[rn]-C[ln])*cnt2
        lc += cnt2
        rn += 1
        rc = 0
    else:
        ans += func(SUM, C[rn]-C[ln], cnt1)
        SUM += (C[rn]-C[ln])*cnt1
        ln += 1
        lc = 0
        rn += 1
        rc = 0

print(ans)