#include <bits/stdc++.h>
using namespace std;
#define si(a) (long)a.size()
#define fi first
#define se second
#define all(x) x.begin(),x.end()
#define rep(i,n) for(int i=0;i<(int)(n);++i)
template<typename S,typename F>bool chmin(S&a,F b){return b<a?(a=b,1):0;}
template<typename S,typename F>bool chmax(S&a,F b){return b>a?(a=b,1):0;}
bool _=(ios::sync_with_stdio(0),cin.tie(0),cout<<fixed<<setprecision(16),0);
#include<atcoder/math>


#define lbi(a,x) (lower_bound(all(a),x)-a.begin())

long f(long n, long m, long a, long b){
    long ret=0;
    ret+=n;
    ret-=atcoder::floor_sum(n,m,a,b+(m-1));
    ret+=atcoder::floor_sum(n,m,a,b);
    return ret;
}


int main(){
    int N,K,M;
    cin>>N>>K>>M;
    vector<long> B(N+1,0);
    vector<long> C(N,0);
    rep(i,N)cin>>B[i+1],B[i+1]+=B[i];
    rep(i,N)cin>>C[i];
    C.push_back(0);

    vector<long> E(N+1,0);
    rep(i,N)E[i+1]=E[i]+(B[i+1]-B[i])*C[i];

    vector<long> D;
    rep(i,N+1){
        D.push_back(B[i]);
        if(B[i]+K<B.back())D.push_back(B[i]+K);
    }
    D.push_back(D.back()+1);

    sort(all(D));
    D.erase(unique(all(D)),D.end());
    auto SUM=[&](long r)->long {
        if(r==0)return 0;
        if(r==B[N]) return E[N];
        int i=lbi(B,r+1)-1;
        return E[i]+(r-B[i])*C[i];
    };
    long ans=0;
    rep(i,si(D)-1){
        if(D[i]<K)continue;
        long w=D[i+1]-D[i];
        int l=lbi(B,D[i]-K);
        int r=lbi(B,D[i]);
        long s=SUM(D[i])-SUM(D[i]-K);
        ans+=f(w,M,C[r]-C[l],s);
    }
    cout<<ans<<"\n";
}