- #include <iostream> 
-   
-   
- long long dp[1<<6]; 
-   
- long long solve(int cnt){ 
-     if(cnt==1 || cnt==2) 
-         return 2; 
-     if(cnt==3) 
-        return 4; 
-     if(!dp[cnt])  
-        return dp[cnt]=solve(cnt-1)+solve(cnt-2); 
-     return dp[cnt] ; 
- } 
- int main() 
- { 
-    int n; 
-    std::cin>>n; 
-    long long ans = solve(n); 
-    std::cout<<ans; 
-    return 0; 
- } 
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