Can someone explain this

Initialisation step: Before the first iteration, the invarianoy is satisfied. Maintenance step: Assuming .s = 2:2 was satisfied until now In the next iteration: New value of x = x+1 New value of s = s(old value) + 2*x(new value) - 1 3ntw = $2+2(I+1)1 = $2+2$+21 = $2+2$+1 = (3+1): = (Iflfw): Hence, invariance of the loop is maintained after the end of the loop