hdu 1165 Eddy's research II

http://acm.hdu.edu.cn/showproblem.php?pid=1165

#include <cstdio>
#include <cstring>
#include <algorithm>
#define ll __int64
using namespace std;

ll A(ll m, ll n)
{
    if(n==0) return A(m-1,1);
    else if(m==1) return n+2;
    else if(m==2) return 2*n+3;
    else return A(m,n-1)*2+3;
}

int main()
{
    ll m,n;
    while(scanf("%I64d%I64d",&m,&n)!=EOF)
    {
        printf("%I64d
",A(m,n));
    }
    return 0;
}