#include <bits/stdc++.h>
using namespace std;
#define int long long
const int LLINF = 2e18 + 10;
const int MAXN = 45;
const int MAXS = 1700;
bool dp[MAXN][MAXN][MAXN * MAXN];
int a[MAXN], b[MAXN];
void solve() {
int n, m, k;
cin >> n >> m >> k;
int sum_a = 0;
for (int i = 1; i <= n; i++) {
cin >> a[i];
sum_a += a[i];
if (a[i] < k) {
cout << "Impossible\n";
return;
}
}
dp[0][0][0] = true;
for (int i = 1; i <= m; i++) {
cin >> b[i];
int x = b[i];
// cout << "processing x = " << x << endl;
for (int r = k; r >= 1; r--) {
for (int c = n; c >= 1; c--) {
for (int s = MAXS - 1; s >= 0; s--) {
int pr, pc, lo;
if (x >= n) {
if (r == 1) {
pr = 0;
pc = 0;
lo = x - c;
} else {
pr = r - 1;
pc = c;
lo = x - n;
}
} else if (x < c) {
pr = r;
pc = x - c;
lo = 0;
} else {
if (r == 1) {
pr = 0;
pc = 0;
lo = x - c;
} else {
pr = r - 1;
pc = n - (x - c);
lo = 0;
}
}
// printf("r = %lld c = %lld s = %lld checking pr = %lld pc = %lld lo = %lld\n", r, c, s, pr, pc, lo);
if (lo <= s && pr >= 0 && pc >= 0 && dp[pr][pc][s - lo]) {
dp[r][c][s] = true;
// printf("dp[%lld][%lld][%lld] = dp[%lld][%lld][%lld] = true\n", r, c, s, pr, pc, s - lo);
}
if (x <= s && dp[r][c][s - x]) {
dp[r][c][s] = true;
// printf("2 dp[%lld][%lld][%lld] = dp[%lld][%lld][%lld] = true\n", r, c, s, r, c, s - x);
}
}
}
}
}
int mini = sum_a - k * n;
for (int s = mini; s < MAXS; s++) {
if (dp[k][n][s]) {
cout << s + k * n - sum_a << "\n";
return;
}
}
cout << "Impossible\n";
}
int32_t main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
solve();
return 0;
}
