include<bits/stdc++.h>

using namespace std;
int main()
{
long long n,k,sott,tong=0,soht;
cin>>n>>k;
soht=n;
tong=n2;
sott=n;
for (int i=2;i<=k;i++)
{
sott=soht2+tong-sott;
tong=tong+sott;
//tong%=1000000007;
soht=sott;
}
cout<<tong;
}