public class Test9 {
public static void main(String[] args) {
double sum1=1.0;
double sum2=1.0;
for(double i=1;i<=99;i+=2){
sum1+=1/i;
}
for(double j=2;j<=100;j+=2){
sum2+=1/j;
}
System.out.println("sum="+(sum1-sum2));
}
}