#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;
int main()
{
    double a[100];
    for(int i=0;i<100;i++)
    {
        cin>>a[i];
        if(a[i]==999)
            break;
        if(i>0)
            printf("%.2lf\n",a[i]-a[i-1]);
    }End of Output
    cout<<"End of Output"<<endl;
    return 0;
}