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) { } }