#include <stdio.h>
#include <string.h>

char n[1001],nr[2002],i,j,l,k,r;

int main(){
    freopen ("sarpe.in","r",stdin);
    freopen ("sarpe.out","w",stdout);
    
    scanf ("%s",n);
    l=strlen(n);
    
    for (i=l-1;i>=0;i--)
        for (j=l-1;j>=0;j--)
            nr[(l-i)+j]+=2*(n[j]-'0')*(n[i]-'0');
    r=0;
    for (i=1;i<=2*l-1;i++)
        if (nr[i]>=10){
           nr[i]+=r;
           r=nr[i]/10;
           nr[i]%=10;
        }
    while(r){
             i++;
             nr[i]=r%10;
             r=r/10;
    }
    k=i;
    for (i=l-1;i>=0;i--)
        nr[l-i]-=2*(n[i]-'0');
    nr[1]+=4;
    for (i=1;i<=k;i++)
        if (nr[i]<0){nr[i]+=10;nr[i+1]--;}
    while (!nr[k])k--;
    for (i=k;i>=1;i--)
    printf("%ld",nr[i]);
    
return 0;
}