#include<stdio.h>
#include<stdlib.h>

int main(){
int p,n,nr,q;
FILE *f;
FILE *g;
f = fopen("fact.in","r");
g = fopen("fact.out","w");
fscanf(f,"%d",&p);
nr = 1;
n = 0;
if (p == 0){
    fprintf(g,"1");
    return 0;
}

while (nr != p){
    n = n+5;
    nr ++;
    q = n;
    if (q%10 == 0)
        q = q/10;
    while (q%10 == 0){
        nr++;
        q = q/10;
    }
}
fprintf(g,"%d",n);
return 0;
}