import std;
void main(){
	auto inputs = readln.chomp.split(" ").to!(long[]);
	ulong M = 10 ^^ 9 + 7;
	auto a = inputs[0];
	ulong r = (a % M) * 2 + 1;
	auto b = inputs[1];
	r *= (b % M);
	r %= M;
	r += a;
	if((a - b) % 2 == 0){
		r += 1;
	}
	writeln(r % M);
}