import std;
void main(){
	auto inputs = readln.chomp.split(" ").to!(long[]);
	auto a = inputs[0];
	auto b = inputs[1];
	auto r = (a * 2 + 1) * b + a;
	if((a - b) % 2 == 0){
		r += 1;
	}
	writeln(r % 1000000007);
}