#include <iostream>
using namespace std;
long int fib2(int n) {
int a = 1;
int b = 1;
for (int i = 3; i <= n; i++){
int pom = a;
a = b;
b = pom + b;
}
return b;
}
int main() {
cout << fib2(4) << endl;
cout << fib2(11) << endl;
return 0;
}
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