import std.conv, std.functional, std.range, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.bitmanip, std.complex, std.container, std.math, std.mathspecial, std.numeric, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }
real readReal() { return readToken.to!real; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }




void main() {
  /*
  debug {
    enum lim = 200L;
    real sum2 = 0.0L;
    foreach (a0; 1 .. lim) foreach (a1; 1 .. lim) {
      sum2 += 1.0L / (1.0L * a0^^4 * a1^^2 * (1.0L / a0^^2 + 1.0L / a1^^2));
    }
    writefln("%.12f", sum2);
    writefln("%.12f", PI^^4 / sum2);
    real sum3 = 0.0L;
    foreach (a0; 1 .. lim) foreach (a1; 1 .. lim) foreach (a2; 1 .. lim) {
      sum3 += 1.0L / (1.0L * a0^^4 * a1^^2 * a2^^2 * (1.0L / a0^^2 + 1.0L / a1^^2 + 1.0L / a2^^2));
    }
    writefln("%.12f", sum3);
    writefln("%.12f", PI^^6 / sum3);
    real sum4 = 0.0L;
    foreach (a0; 1 .. lim) foreach (a1; 1 .. lim) foreach (a2; 1 .. lim) foreach (a3; 1 .. lim) {
      sum4 += 1.0L / (1.0L * a0^^4 * a1^^2 * a2^^2 * a3^^2 * (1.0L / a0^^2 + 1.0L / a1^^2 + 1.0L / a2^^2 + 1.0L / a3^^2));
    }
    writefln("%.12f", sum4);
    writefln("%.12f", PI^^8 / sum4);
  }
  */
/*
1.344671338542
72.440817500887
1.470103666923
653.960135741817
1.808141008697
5247.672040196820
*/
  
  try {
    for (; ; ) {
      const N = readInt();
      
      writeln(cast(int)(floor(sqrt(1.0L * N))));
    }
  } catch (EOFException e) {
  }
}