main(a){a=getchar();if(a==50)puts("0.4306765580733930506701065687639656320697919320797604493219760379606620825378855060836980994452669756");if(a==49)puts("1.0913291693220690405244902073659644617714807626004721801186465050859043169457061816626305150819854494");if(a==53)puts("2.8502198590705460801984063271283473668142182008955186847692317629214275933165126500736882651405774481");}
Note that non-ascii characters in the above source code will be escaped (such as \x9f).