/*
欧拉计划第16题， 计算 2 ^ 100, 各个数位上的数字之和
answer: 1366
*/

#include<bits/stdc++.h>

using namespace std;

vector<int> mul(vector<int> A, int x)
{
    int c = 0, n = A.size(), i = 0;
    vector<int> ans;

    reverse(A.begin(), A.end());

    while (i < n)
    {
        c += A[i] * x;
        ans.push_back(c % 10);
        c /= 10;
        i ++;
    }

    while (c)
    {
        ans.push_back(c % 10);
        c /= 10;
    }

    reverse(ans.begin(), ans.end());

    return ans;
}
int main(void)
{
    vector<int> ans;
    ans.push_back(2);

    for (int i = 2; i <= 1000; ++ i)
        ans = mul(ans, 2);

    int sum = 0;
    for (int i = 0; i < ans.size(); ++ i) sum += ans[i];

    cout << sum << endl;

    return 0;
}