#include<stdio.h>
FILE *f1,*f2;
int main ()
{long unsigned p,x,nr,y;
f1=fopen("fact.in","r");
f2=fopen("fact.out","w");
fscanf(f1,"%lu",&p);
if(p==0)x=1;
else {x=5;nr=1;
while(nr<p){x+=5;y=x;
while(y%5==0){nr++;y=y/5;}}}
fprintf(f2,"%lu\n",x);
fclose(f1);
fclose(f2);
return 0;}