#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 dp3[maxn][maxn*maxn];
int dp4[40][40*40][40*40];
int rec3 (int i, int sm) {
if (sm >= smA) return sm - smA;
if (i == m) return 1e9;
if (dp3[i][sm] != -1) return dp3[i][sm];
return dp3[i][sm] = min(rec3(i + 1, sm), rec3(i + 1, sm + B[i]));
}
int rec4 (int i, int sm, int sm2) {
if (i == m) {
if (sm >= smA and sm2/n >= k) return sm - smA;
return 1e9;
}
if (dp4[i][sm][sm2] != -1) return dp4[i][sm][sm2];
return dp4[i][sm][sm2] = max(rec4(i + 1, sm, sm2), rec4(i + 1, sm + B[i], sm2 + 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;
}
if (m <= 15) { // subtasks 1 and 2
for (int i = 0 ; i < (1 << m) ; i++) {
smB = 0, cntBN = 0;
if (__builtin_popcount(i) < k) continue;
for (int j = 0 ; j < m ; j++) {
if (i & (1 << j)) {
smB += B[j];
cntBN += min(n, B[j]);
}
}
if (smB >= smA and cntBN/n >= k) ans = min(ans, smB - smA);
}
cout << ans << endl;
return 0;
}
if (k == 1) {
memset(dp3, -1, sizeof dp3);
cout << rec3(0, 0) << endl;
return 0;
}
if (max({n, m, k, *max_element(A, A+n), *max_element(B,B+m)}) <= 40) {
for(int i=0;i<40;i++) for(int j=0;j<40*40;j++) for(int k=0;k<40;k++) dp4[i][j][k]=-1;
cout << rec4(0,0,0) << endl;
return 0;
}
}
