Solution:1st letter: A + 5 = F , F + 5 = K, K + 5 = P , P + 5 = U , U + 5 = Z
2nd letter: G + 4 = K , K + 4 = O , O + 4 = S, S + 4 = W , W + 4 = A
3rd letter: P + 3 = S , S + 3 = V , V + 3 = Y , Y + 3 = B , B + 3 = E
4th letter: L + 2 = N , N + 2 = P , P + 2 = R , R + 2 = T , T + 2 = V
5th letter: H + 1 = I , I + 1 = J , J + 1 = K , K + 1 = L , L + 1 = M