import std.algorithm, std.container, std.conv, std.math, std.range, std.typecons, std.stdio, std.string; auto rdsp(){return readln.splitter;} void pick(R,T)(ref R r,ref T t){t=r.front.to!T;r.popFront;} void readV(T...)(ref T t){auto r=rdsp;foreach(ref v;t)pick(r,v);} void readC(T...)(size_t n,ref T t){foreach(ref v;t)v=new typeof(v)(n);foreach(i;0..n){auto r=rdsp;foreach(ref v;t)pick(r,v[i]);}} const mod = 10^^9+7; alias mint = FactorRing!mod; void main() { int n; readV(n); int[] a; readC(n+1, a); int[] b; readC(n+1, b); auto s = mint(0), sb = mint(0); foreach (i; 0..n+1) { sb += b[i]; s += sb*a[n-i]; } writeln(s); } 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); } }