var a,b,i,j:longint;
       f:array[0..maxlongint,0..maxlongint] of longint;
 function max(a,b:longint):longint;
 begin
   if a>b then exit(a) else exit(b);
 end;
 begin
    readln(a,b);
    for i:=1 to a do
     for j:=1 to b do
      f[i,j]:=max(f[i-1,j],f[i,j-1])+1;
    writeln(f[a,b]);
 end.

nice solution :D
another solution with recursion

#include <iostream>

using namespace std;

int add(int a , int b)
{
    if (a <= 1 && b <= 1)
       return a + b;

    return add(a / 2 , b / 2) + add(a / 2, b / 2) + (b % 2) + (a % 2);
}
int main()
{
    int a , b;
    cin>>a>>b;
    cout<<add(a,b)<<endl;
    return 0;
}

Are your shure, that it is Problem № 1000 ?

O_o