注意a[i] + b[1]大于p和a[i] + b[m]小于p两种情况
#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 10;
typedef long long ll;
ll n, m, p;
ll a[N], b[N];
ll s[N];
ll ans;

bool check(int x, ll a){
    if(b[x] + a < p)return false;
    return true;
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cin >> n >> m >> p;
    for(int i = 1;i <= n;i++)cin >> a[i];
    for(int j = 1;j <= m;j++)cin >> b[j];
    sort(b + 1, b + 1 + m);
    for(int i = 1;i <= m;i++)s[i] = s[i - 1] + b[i];

    for(int i = 1;i <= n;i++){
        if(a[i] + b[m] < p){
            ans += m * a[i] + s[m];
            continue;
        }
    ll l = 1, r = m;
    while(l < r){
        int mid = (l + r) >> 1;
        if(check(mid, a[i]))r = mid;
        else l = mid + 1;
    }
    // cout << l  << " ";
    ans += (l - 1) * a[i] + s[l - 1];
    ans += (m - l + 1) * p;
    // cout << ans << endl;
    }
    cout << ans;

    return 0;
}