N,K,mod=map(int,input().split())
B=list(map(int,input().split()))
C=list(map(int,input().split()))
posa=0
resta=B[0]
count=0
score=0
for i in range(N):
  if count+B[i]>=K:
    posb=i
    restb=count+B[i]-K
    score+=C[i]*(K-count)
    score%=mod
    break
  else:
    count+=B[i]
    score+=C[i]*B[i]
    score%=mod
result=0
from math import gcd
while True:
  d=(C[posa]-C[posb])%mod
  n0=resta
  n1=restb+1
  if n1<=n0:
    if d==0:
      if score==0:
        result+=n1
    else:
      y=gcd(d,mod)
      if score%y==0:
        w=score//y
        t=d//y
        mod2=mod//y
        x=(w*pow(t,-1,mod2))%mod2
        result+=(n1-1-x)//mod2+1
    score-=C[posa]*n1
    score+=C[posb]*(n1-1)
    if posb==N-1:
      break
    posb+=1
    score+=C[posb]
    score%=mod
    restb=B[posb]-1
    resta-=n1
  else:
    if d==0:
      if score==0:
        result+=n0
    else:
      y=gcd(d,mod)
      if score%y==0:
        w=score//y
        t=d//y
        mod2=mod//y
        x=(w*pow(t,-1,mod2))%mod2
        result+=(n0-1-x)//mod2+1
    score-=C[posa]*n0
    score+=C[posb]*n0
    posa+=1
    restb-=n0
    resta=B[posa]
print(result)