#include <iostream>
#include <fstream>

int good(unsigned long long x, unsigned long long key)
{
    if (x * x > key || x == 4294967296)
        return 1;
    return 0;
}

unsigned long long int bin(unsigned long long key)
{
    unsigned long long int left, right, mid;
    left = 0;
    right = 1;
    while (right * 2 <= 4294967296) {
        right *= 2;
        if (good(right, key))
            break;
    }
    while (right - left != 1) {
        mid = (left + right) / 2;
        if (good(mid, key))
            right = mid;
        else if (!good(mid, key))
            left = mid;
    }
    return left;
}


int main()
{
    std::ifstream fin("input.txt");
    std::ofstream fout("output.txt");
    unsigned long long int input;
    while (fin >> input){
        fout << bin(input) << std::endl;
    }

    fin.close();
    fout.close();

    return 0;
}