07. Noise

#include <iostream>
#include <string>
#include <cctype>
#include <cmath>

using namespace std;

int main() {
    string str, number;
    getline(cin, str);

    for (int i = 0; str[i] != '.'; i++) {
        if (isdigit(str[i])) {
            number += str[i];
        }
    }

    cout << sqrt(stoi(number)) << endl;
    return 0;
}