#include <bits/stdc++.h>
using namespace std;
#define MAXN 45
#define int long long
int n,m,k;
int a[MAXN],b[MAXN];
vector<int> grt;
bool dp[MAXN*MAXN];
bool newdp[MAXN][MAXN*MAXN];
int32_t main()
{
cin>>n>>m>>k;
for (int i=1;i<=n;i++) cin>>a[i];
for (int i=1;i<=m;i++) cin>>b[i];
for (int i=1;i<=n;i++)
{
if (a[i]<k) {cout<<"Impossible"<<endl;return 0;}
}
int suma=0;for (int i=1;i<=n;i++) suma+=a[i];
grt.push_back(0);int sumb=0;for (int i=1;i<=m;i++) sumb+=b[i];
dp[0]=true;for (int val=1;val<=sumb;val++) dp[val]=false;
for (int i=1;i<=m;i++)
{
if (b[i]>=n) {grt.push_back(b[i]);continue;}
for (int val=sumb;val>=0;val--)
{
if (val+b[i]>=MAXN*MAXN) continue;
if (dp[val]==true) dp[val+b[i]]=true;
}
}
for (int number=0;number<(int)grt.size();number++)
{
for (int val=0;val<=sumb;val++) newdp[number][val]=false;
}
newdp[0][0]=true;
for (int pos=1;pos<(int)grt.size();pos++)
{
for (int number=(int)grt.size()-1;number>=1;number--)
{
for (int val=sumb;val>=0;val--)
{
if (val+grt[pos]>=MAXN*MAXN) continue;
if (newdp[number-1][val]==true) newdp[number][val+grt[pos]]=true;
}
}
}
int answer=INT_MAX;
for (int val=0;val<=sumb;val++)
{
if (dp[val]==false) continue;
int num_greater=k-(val+n-1)/n;
if (num_greater<0) num_greater=0;
else if (num_greater>=(int)grt.size()) continue;
int fali=max((long long)0,suma-val);
for (int value=fali;value<=sumb;value++)
{
if (newdp[num_greater][value]) {answer=min(answer,val+value-suma);break;}
}
}
if (answer==INT_MAX) cout<<"Impossible"<<endl;
else cout<<answer<<endl;
return 0;
}
