#include <bits/stdc++.h>
using namespace std;
double a,b,c,d;
int main()
{
cin>>a>>b>>c>>d;
cout<<a+b+c+d;
return 0;
}
Var a,b,c,d,s:real;
Begin
Write('nhap so thu nhat ');readln(a);
Write('nhap so thu hai ');readln(b);
Write('nhap so thu ba ');readln(c);
Write('nhap so thu tu ');readln(d);
s:=a+b+c+d;
Write('tong la ',s:10:2);
Readln;
End.