#include <bits/stdc++.h>
#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx,avx2,fma")
using namespace std;
const int N = 300 * 300 + 5;
bool visited[305][N];
int ndp[N];
const int maxN = 305;
int a[maxN], b[maxN], long_ids[maxN], short_ids[maxN];
const int inf = 1000000000;
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
bool found = false;
int n, m, k;
cin >> n >> m >> k;
int tot = 0;
for (int i = 0; i < n; i++) {
cin >> a[i];
tot += a[i];
if (a[i] < k) {
found = true;
}
}
for (int i = 0; i < m; i++) {
cin >> b[i];
}
int ans = inf;
if (!found) {
int ptr_long = 0, ptr_short = 0;
for (int i = 0; i < m; i++) {
if (b[i] >= n) {
long_ids[ptr_long++] = i;
} else {
short_ids[ptr_short++] = i;
}
}
ndp[0] = 1;
for (int i = 0; i < ptr_long; i++) {
for (int it = N - 1 - b[long_ids[i]]; it >= 0; it--) {
if (ndp[it] > 0) {
ndp[it + b[long_ids[i]]] = max(ndp[it + b[long_ids[i]]], ndp[it] + 1);
}
}
}
for (int i = 0; i < N; i++) {
if (ndp[i] > 0) --ndp[i];
}
function<void(int, int)> Rec = [&](int i, int sum) {
if (visited[i][sum]) {
return ;
}
if (i == ptr_short) {
if (sum >= max(n * k, tot)) {
ans = min(ans, sum - tot);
return ;
}
int ptr = tot - sum;
while (ptr < N && sum + n * ndp[ptr] < n * k) ptr++;
if (ptr < N && ndp[ptr] > 0) {
ans = min(ans, sum + ptr - tot);
}
visited[i][sum] = true;
return ;
}
Rec(i + 1, sum + b[short_ids[i]]);
Rec(i + 1, sum);
visited[i][sum] = true;
return ;
};
Rec(0, 0);
}
if (ans < inf && !found) {
cout << ans << '\n';
} else {
cout << "Impossible\n";
}
return 0;
}
