import List;

public int dotProduct(list[int] L, list[int] M){
	result = 0;
	if(size(L) == size(M)) {
		while(size(L) >= 1) {
		    result += (head(L) * head(M));
		    L = tail(L);
		    M = tail(M);
	        }
	        return result;
	}
	else {
		throw "vector sizes must match";
	}
}