#include <bits/stdc++.h>
using namespace std;
int const INF=1e9;
int const MAX=305;
bitset<MAX*MAX>dp1[MAX];
bitset<MAX*MAX>dp2[MAX];
int n,m,k;
int a[MAX],b[MAX];
int summin[MAX][MAX*MAX];
int cnt1,cnt2;
int sum1,sum2;
void add(bitset<MAX*MAX>dp[],int val,int cap){
int i;
for(i=cap;i;--i)
dp[i]|=(dp[i-1]<<val);
}
void read(){
cin>>n>>m>>k;
int i;
for(i=1;i<=n;++i)
cin>>a[i];
for(i=1;i<=m;++i)
cin>>b[i];
}
bool check(){
if(m<k)
return 0;
int i;
for(i=1;i<=n;++i){
if(a[i]<k)
return 0;
sum1+=a[i];
}
int c1=0,c2=0,s2=0;
for(i=1;i<=m;++i){
sum2+=b[i];
if(b[i]>=n)
++c1;
else{
++c2;
s2+=b[i];
}
}
if(c1<k && s2<(k-c1)*n)
return 0;
if(sum1>sum2)
return 0;
return 1;
}
void create_knapsacks(){
dp1[0][0]=1;
dp2[0][0]=1;
int i;
for(i=1;i<=m;++i)
if(b[i]>=n){
++cnt1;
add(dp1,b[i],cnt1);
}
else{
++cnt2;
add(dp2,b[i],cnt2);
}
}
void create_summin(){
int i,j;
for(i=MAX-1;i>=0;--i)
for(j=MAX*MAX-1;j>=0;--j){
if(i==MAX-1 || j==MAX*MAX-1){
summin[i][j]=INF;
continue;
}
if(dp2[i][j])
summin[i][j]=j;
else
summin[i][j]=min(summin[i+1][j],summin[i][j+1]);
}
}
void minself(int& x,int val){
if(x>val)
x=val;
}
int solve(){
int ans=INF;
int i,j;
for(i=0;i<=cnt1;++i)
for(j=0;j<=sum2;++j)
if(dp1[i][j]){
int nrc=max(0,k-i);
int sum=max(0,max(sum1-j,(k-i)*n));
minself(ans,j+summin[nrc][sum]-sum1);
}
return ans;
}
int main()
{
read();
if(!check()){
cout<<"Impossible";
return 0;
}
create_knapsacks();
create_summin();
cout<<solve();
return 0;
}
