In an electrochemical reaction of lead, at standard temperature, if \( E^\circ_{(\mathrm{Pb^{2+}/Pb)}} = m \) Volt and \( E^\circ_{(\mathrm{Pb^{4+}/Pb)}} = n \) Volt, then the value of \( E^\circ_{(\mathrm{Pb^{2+}/Pb^{4+}})} \) is given by \( m - xn \). The value of \( x \) is _______. (Nearest integer)
