process.stdin.resume();
process.stdin.setEncoding('utf8');
process.stdin.on('data', function(chunk) {
    main(chunk.trim());
});
function main(chunk){
    // your code goes here
    chunk = chunk.replace(/[^0-9]/g,"");
    var ans = 0;
    for(var i in chunk){
        ans += Number(chunk[i]);
    }
    console.log(ans);
}