import java.util.Scanner;

public class Solution {
    // 1. 先定义 mysqrt(int) 方法(实例方法,public 权限)
    public int mysqrt(int x) {
        if (x == 0 || x == 1) {
            return x;
        }
        for (int i = 1; i <= x; i++) {
            if (i * i == x) {
                return i;
            } else if (i * i > x) {
                return i - 1;
            }
        }
        return 0;
    }

    // 2. 在 main 方法中实例化 Solution,再调用 mysqrt 方法
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int x = sc.nextInt();

        Solution solution = new Solution();
    
        int ret = solution.mysqrt(x);

        System.out.println(ret);
        sc.close();
    }
}