Letters that make output-to-input ratio
a, o, n, p, r, t, i, u are letters that make 'output-to-input ratio'
Words within output-to-input ratio
input, ti, NP, at, ratio, ut, out, in, put, output, rat, RA, IN, Io, Ra, At, In, Np, Pu, Ti, UT are words within 'output-to-input ratio'