#include <cstdio>#include <string>#include <iostream>#include <algorithm>#include <vector>#include <queue>#include <stack>#include <set>#include <map>#include <string>#include <math.h>#include <stdlib.h>#include <bitset>using namespace std;#define ll long longint main(){    ll ans = 0,i,j,num,k;    string s;    cin>>s;    int len = s.size();    for(i=0;i<len;i++){        num = s[i]-‘0‘;        if(num%4==0)            ans++;    }    //cout<<ans<<endl;    if(len>=2){    for(i=0;i<len-1;i++){        num = (s[i] - ‘0‘)*10+(s[i+1]-‘0‘);        if(num%4==0)            ans++;    }    }    //cout<<ans<<endl;    if(len>=3){        for(i=0;i<len-1;i++){            num  = (s[i] - ‘0‘)*10+(s[i+1]-‘0‘);            if(num%4==0){                ans+=i;            }            //cout<<ans<<endl;        }    }    cout<<ans<<endl;}