sum chiffres * first

//sum chiffres * first
const s = readline();
if(s.replace(/^-/,'').replace(/[0-9]*/,'').length != 0) {
    print('INVALID')
    return
}
let first = s[0] != '-' ? s[0] : s[1]*-1
let n = s.replace(/^-/,'').replace(/^./,'')
print(n.split('').reduce((a,b)=>a+b*1,0)*first)