#include<iostream>
#include<string>
#include<cstring>
#include<iomanip>
#include<algorithm>
#include<cmath>
#define ll long long
using namespace std;
ll a,b,c,d,e;
ll cnt=0;
string s;
int main(){
    cin>>a>>b>>c>>d>>e;
    for(int i=c;i<=d;i++){
        cnt=0;
        for(int j=a;j<=b;j++){
            ll i1=i;
            s="";
            while(i1>0){
                s+=i1%j+'0';
                i1/=j;
            }
            reverse(s.begin(),s.end());
            bool flag=1;
            ll len=s.size();
            char a1=s[0],a2=s[1];
            if(a1==a2)continue;
            for(int k=2;k<len;k++){
                if(k%2==0){
                    if(s[k]!=a1)flag=0;
                }else{
                    if(s[k]!=a2)flag=0;
                }
            }
            if(flag)cnt++;
        }
        if(cnt==e)cout<<i<<endl;
    }
    return 0;
}