//Variable declaration
H0=64*10**3;    //initial field(ampere/m)
T=5;    //temperature(K)
Tc=7.26;   //transition temperature(K)

//Calculation
H=H0*(1-(T/Tc)**2);     //critical field(ampere/m)

//Result
printf('critical field is %0.3f     *10**3 ampere/m   \n',(H/10**3))