Sums + number theory

Number Theory Level 3

$\text{lcm}(1,77) + \text{lcm}(2,77) + \text{lcm}(3,77) + \cdots + \text{lcm}(77,77) = \, ?$

Notation: $\text{lcm}(a,b)$ denote the Lowest Common Multiple of $a$ and $b$ .