#include #include #include using namespace std;

typedef long long ll;

int main() { int N, M, P; cin >> N >> M >> P;

vector<int> A(N);
for (int i = 0; i < N; i++) {
    cin >> A[i];
}

vector<int> B(M);
for (int i = 0; i < M; i++) {
    cin >> B[i];
}

// 对 B 排序并计算前缀和
sort(B.begin(), B.end());
vector<ll> pref(M + 1, 0);
for (int i = 0; i < M; i++) {
    pref[i + 1] = pref[i] + B[i];
}

ll total = 0;
for (int i = 0; i < N; i++) {
    int threshold = P - A[i];
    
    // 找到第一个 >= threshold 的位置
    int pos = lower_bound(B.begin(), B.end(), threshold) - B.begin();
    
    // 第一类：B_j < threshold
    ll cnt1 = pos;
    total += cnt1 * A[i] + pref[pos];
    
    // 第二类：B_j >= threshold
    ll cnt2 = M - pos;
    total += cnt2 * P;
}

cout << total << endl;

return 0;

}