/*
cf : F112
/) /) ~ ┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┃
( •-• ) ~ ♡ You are amazing ♡
/ づづ ~ ┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛
*/
#include <bits/stdc++.h>
using namespace std;
#define F first
#define S second
#define int long long
#define Ali ios::sync_with_stdio(false), cin.tie(0), cout.tie(0)
const int N = 1e5 + 7;
const int P = 233;
const int len = 250;
const int MOD = 1e9 + 7;
const int inf = 1e18;
int gcd(int x, int y){
while(y){
x %= y;
swap(x, y);
}
return x;
}
int binpow(int n, int k){
if (k == 0) return 1;
if (k % 2 == 0){
int val = binpow(n, k / 2);
return (val * val) % MOD;
}
return (n * binpow(n, k - 1)) % MOD;
}
void abb() {
int n, m, k;
cin >> n >> m >> k;
vector < int > a(n + 1);
vector < int > b(m + 1);
int sumb = 0, suma = 0;
for (int i = 1; i <= n; ++i) cin >> a[i], suma += a[i];
for (int i = 1; i <= m; ++i) cin >> b[i], sumb += b[i];
if (sumb < suma){
cout << "Impossible\n";
return;
}
vector < bool > dp(sumb + 1, 0);
dp[0] = 1;
for (int i = 1; i <= sumb; ++i){
for (int j = 1; j <= m; ++j){
if (i - b[j] >= 0){
dp[i] = (dp[i] | dp[i - b[j]]);
}
}
}
for (int i = suma; i <= sumb; ++i){
if (dp[i] == true){
cout << i - suma << "\n";
return;
}
}
cout << "Impossible\n";
}
signed main(){
Ali;
int T = 1;
// cin >> T;
while(T--){
abb();
}
}
