import std;

long sumDivisors(long n) {
    long sum = 0;
    for (long i = 1; i * i <= n; i++) {
        if (n % i == 0) {
            sum += i;
            if (n / i != i) sum += n / i;
        }
    }
    return sum;
}

void main() {
    long n; scan(n);
    writeln(sumDivisors(n));
}

void scan(T...)(ref T a) {
    string[] ss = readln.split;
    foreach (i, t; T) a[i] = ss[i].to!t;
}
T read(T)() { return readln.chomp.to!T; }
T[] reads(T)() { return readln.split.to!(T[]); }
alias readint = read!int;
alias readints = reads!int;