#include <iostream>
using namespace std;
int somma(int a, int b)
{
if (a==b)
{
return a;
}
else
{
if(a>b)
{
int t=a;
a=b;
b=t;
}
return a+somma(a+1, b);
}
}
int x,y;
int main() {
cin>>x;
cin>>y;
cout<<somma(x,y);
return 0;
}
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