13
To input: D, E, F, d, e, f ‒ dial ‘3’
To input: G, H, I, g, h, I ‒ dial ‘4’
To input: J, K, L, j, k, l ‒ dial ‘5’
To input: M, N, O, m, n, o ‒ dial ‘6’
To input: P, Q, R, S, p, q, r, s ‒ dial ‘7’
To input: T, U, V, t, u, v ‒ dial ‘8’
To input: W, X, Y, Z, w, x, y, z ‒ dial ‘9’
To input any other characters ‒ dial ‘0’
E.g. “@dmin123” = ‘03646123’