import std.algorithm, std.conv, std.range, std.stdio, std.string; import std.bitmanip; // BitArray void readV(T...)(ref T t){auto r=readln.splitter;foreach(ref v;t){v=r.front.to!(typeof(v));r.popFront;}} T[] readArray(T)(size_t n){auto a=new T[](n),r=readln.splitter;foreach(ref v;a){v=r.front.to!T;r.popFront;}return a;} T[] readArrayM(T)(size_t n){auto a=new T[](n);foreach(ref v;a)v=readln.chomp.to!T;return a;} const mod = 10^^9+7; alias mint = FactorRing!mod; void main() { int n, m; readV(n, m); auto p = primes(n); auto s = mint(0), w = n/m; foreach (k; 1..w+1) { s += w; auto f = factors(k, p); foreach (i; 1..(1< 1) { if (k % p[i] == 0) { if (r.empty || r[$-1] != p[i]) r ~= p[i]; k /= p[i]; } else { ++i; } } return r; } pragma(inline) { import core.bitop; pure int bsf(T)(T n) { return core.bitop.bsf(ulong(n)); } pure int bsr(T)(T n) { return core.bitop.bsr(ulong(n)); } pure int popcnt(T)(T n) { return core.bitop.popcnt(ulong(n)); } } pure T[] primes(T)(T n) { import std.algorithm, std.bitmanip, std.conv, std.range; auto sieve = BitArray(); sieve.length((n+1)/2); sieve = ~sieve; foreach (p; 1..((nsqrt(n)-1)/2+1)) if (sieve[p]) for (auto q = p*3+1; q < (n+1)/2; q += p*2+1) sieve[q] = false; auto r = sieve.bitsSet.map!(to!T).map!("a*2+1").array; r[0] = 2; return r; } pure T nsqrt(T)(T n) { import std.algorithm, std.conv, std.range, core.bitop; if (n <= 1) return n; T m = 1 << (n.bsr/2+1); return iota(1, m).map!"a*a".assumeSorted!"a <= b".lowerBound(n).length.to!T; } struct FactorRing(int m, bool pos = false) { version(BigEndian) union { long vl; struct { int vi2; int vi; } } else union { long vl; int vi; } alias FR = FactorRing!(m, pos); @property static init() { return FR(0); } @property int value() { return vi; } @property void value(int v) { vi = mod(v); } alias value this; this(int v) { vi = v; } this(int v, bool runMod) { vi = runMod ? mod(v) : v; } this(long v) { vi = mod(v); } ref auto opAssign(int v) { vi = v; return this; } pure auto mod(int v) const { static if (pos) return v%m; else return (v%m+m)%m; } pure auto mod(long v) const { static if (pos) return cast(int)(v%m); else return cast(int)((v%m+m)%m); } static if (!pos) pure ref auto opUnary(string op: "-")() { return FR(mod(-vi)); } static if (m < int.max / 2) { pure ref auto opBinary(string op)(int r) if (op == "+" || op == "-") { return FR(mod(mixin("vi"~op~"r"))); } ref auto opOpAssign(string op)(int r) if (op == "+" || op == "-") { vi = mod(mixin("vi"~op~"r")); return this; } } else { pure ref auto opBinary(string op)(int r) if (op == "+" || op == "-") { return FR(mod(mixin("vl"~op~"r"))); } ref auto opOpAssign(string op)(int r) if (op == "+" || op == "-") { vi = mod(mixin("vl"~op~"r")); return this; } } pure ref auto opBinary(string op: "*")(int r) { return FR(mod(vl*r)); } ref auto opOpAssign(string op: "*")(int r) { vi = mod(vl*r); return this; } pure ref auto opBinary(string op)(ref FR r) if (op == "+" || op == "-" || op == "*") { return opBinary!op(r.vi); } ref auto opOpAssign(string op)(ref FR r) if (op == "+" || op == "-" || op == "*") { return opOpAssign!op(r.vi); } }