let input=[
    '1020340567.89',
    ];

let print = this.print || console.log;
let gets = this.gets || ((arr, index) => () => arr[index++])(input, 0);

let a=+gets();

function crook(num){
var sum=0;
num=num.toString().split("");
    for(let i=0;i<num.length;i++){
    if (num[i] === '.' || num[i] ==='-'){
            continue;
        }
        sum+= parseInt(num[i],10);
    }
    return sum;
}

let b=crook(a);

while(b>9){
    b=crook(b);
}

print(b);