#include <fstream>

using namespace std;

int main()
{
    ifstream fin("fact.in");
    long long p,n,i,x;
    fin>>p;
    fin.close();
    n=0;
    i=1;
    ofstream fout("fact.out");
    while(n<=p)
    {
        if(i%10==5) n++;
        else if(i%10000000==0) n+=7;
        else if(i%1000000==0) n+=6;
        else if(i%100000==0) n+=5;
        else if(i%10000==0) n+=4;
        else if(i%1000==0) n+=3;
        else if(i%100==0) n+=2;
        else if(i%10==0) n++;
        if(n==p) {x=i;break;}
        i++;
    }
    fout<<x<<"\n";
    fout.close();
    return 0;
}