#pragma GCC optimize ("Ofast")
#pragma GCC target ("avx,avx2,fma")
#include"bits/stdc++.h"
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
template<class x>
using ordered_set = tree<x, null_type,less<x>, rb_tree_tag,tree_order_statistics_node_update>;
#define int long long
#define endl '\n'
#define mod 1000000007
//\
#define mod 1686876991
const int maxn = 301;
int n, m, k, cntAK, cntBN, smA, smB, ans = 1e9;
int A[maxn], B[maxn];
int dp[maxn][maxn*maxn];
int rec (int i, int sm) {
if (sm == 0) return 0;
if (i == m || sm < 0) return -INT_MAX;
if (dp[i][sm] != -1) return dp[i][sm];
return dp[i][sm] = max(rec(i + 1, sm), rec(i + 1, sm - B[i]) + min(B[i], n));
}
signed main () {
cin.tie(0)->sync_with_stdio(0);
cin >> n >> m >> k;
for (int i = 0 ; i < n ; i++) {
cin >> A[i];
smA += A[i];
if (A[i] < k) cntAK++;
}
for (int i = 0 ; i < m ; i++) {
cin >> B[i];
cntBN += min(n, B[i]);
smB += B[i];
}
if (m < k || smB < smA || cntBN/n < k || cntAK) {
// assert(0);
cout << "Impossible\n";
return 0;
}
memset(dp, -1, sizeof dp);
for (int i = smA ; i < maxn * maxn ; i++) {
if (rec(0, i) / n >= k) {
ans = min(ans, i - smA);
break;
}
}
cout << ans << endl;
}
/*
impossible:
- M < K
- sum of B < sum of A
- the number of (B >= N) is < K
- theres an A which is < K
*/
