Recursive code for Fibonacci Number

class Solution {
public:
    int fib(int n) {
        if(n<=1)
            return n;
        return fib(n-1)+fib(n-2);

    }
};
/*
F(0)=0
F(1)=1
F(2)=1
F(3)=2
F(4)=3
F(5)=5
*/