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)); } int root(int[] uf, int u) { return (uf[u] < 0) ? u : (uf[u] = uf.root(uf[u])); } bool connect(int[] uf, int u, int v) { u = uf.root(u); v = uf.root(v); if (u == v) return false; if (uf[u] > uf[v]) swap(u, v); uf[u] += uf[v]; uf[v] = u; return true; } void main() { try { for (; ; ) { const L = readInt(); const R = readInt(); auto uf = new int[R + 1]; uf[] = -1; foreach (a; L .. R + 1) { for (int b = 2 * a; b <= R; b += a) { uf.connect(a, b); } } int numComps; foreach (a; L .. R + 1) { if (uf[a] < 0) { ++numComps; } } writeln(numComps - 1); } } catch (EOFException e) { } }