void main() {
	auto N = ri;
	auto A = readAs!(int[]);
	auto B = readAs!(int[]);
	auto used = new bool[](N);
	foreach(ai, av; A) {
		if(B[ai] <= av) continue;
		
		int tmp = av;
		bool flag = false;
		foreach(ai2, av2; A) {
			if(ai == ai2) continue;
			if(av2 > B[ai2]) {
				auto ad = min(av2 - B[ai2], B[ai] - tmp);
				tmp += ad;
				A[ai2] -= ad;
				used[ai2] = true;
				used[ai] = true;
			}
			if(tmp ==  B[ai]) {
				flag = true;
				break;
			}
		}
		if(!flag) {
			writeln("-1");
			return;
		}
	}
	used.count!"a".writeln;
}

// ===================================

import std.stdio;
import std.string;
import std.functional;
import std.algorithm;
import std.range;
import std.traits;
import std.math;
import std.container;
import std.bigint;
import std.numeric;
import std.conv;
import std.typecons;
import std.uni;
import std.ascii;
import std.bitmanip;
import core.bitop;

T readAs(T)() if (isBasicType!T) {
	return readln.chomp.to!T;
}
T readAs(T)() if (isArray!T) {
	return readln.split.to!T;
}

T[][] readMatrix(T)(uint height, uint width) if (!isSomeChar!T) {
	auto res = new T[][](height, width);
	foreach(i; 0..height) {
		res[i] = readAs!(T[]);
	}
	return res;
}

T[][] readMatrix(T)(uint height, uint width) if (isSomeChar!T) {
	auto res = new T[][](height, width);
	foreach(i; 0..height) {
		auto s = rs;
		foreach(j; 0..width) res[i][j] = s[j].to!T;
	}
	return res;
}

int ri() {
	return readAs!int;
}

double rd() {
	return readAs!double;
}

string rs() {
	return readln.chomp;
}
