#include <stdio.h>

int main(){
    FILE *fin, *fout;
    fin=fopen("fact.in", "r");
    fout=fopen("fact.out", "w");

    int p, gasit, cn, n, e2, e5;

    fscanf(fin, "%d", &p);

    if(p==0){
        n=1;
    }
    else{
        n=2;
        e2=0;
        e5=0;
        gasit=0;
        while(gasit==0){
                cn=n;
                while(cn%2==0){
                    e2++;
                    cn=cn/2;
                }
                while(cn%5==0){
                    e5++;
                    cn=cn/5;
                }
                if(e2>e5){
                    if(e5==p){
                        gasit=1;
                    }
                }
                else{
                    if(e2==p){
                        gasit=1;
                    }
                }
                if(gasit==0){
                    n++;
                }
        }

    }
    fprintf(fout, "%d", n);
    fclose(fin);
    fclose(fout);
    return 0;
}