#include <stdio.h>

int main(){
	FILE *fin,*fout;
	long int P,k,m;
	long int N;
	
	fin=fopen("fact.in","rt");
	fout=fopen("fact.out","wt");
	
	fscanf(fin,"%ld",&P);
	
	if (P==0){
		N=1;
		fprintf(fout,"%ld",N);
		return 0;
	}
	
	N=k=0;
	
	while(1){
		N+=5;
		m=N;
		while (m%5==0){
			m/=5;
			k++;
		}
		
		if (k==P){
			fprintf(fout,"%ld",N);
			return 0;
		}
	}
	
	
	return 0;
}