text: #include<bits/stdc++.h>
  #include<stdint.h>
  using namespace std;
  #define IOS {cin.tie(nullptr);ios_base::sync_with_stdio(false);}
  #define N 1000000
  
  void print(__int128 ans){
  	static int64_t s[40];
  	int top = 0;
  	while(ans > 0){
  		s[top++] = ans%10000000000000000ll;
  		ans/=10000000000000000ll;
  	}
  	cout << s[top-1]; 
  	for(int i=top-2;i>=0;i--) cout << setfill('0') << setw(16) << s[i];
  	cout << '\n';
  }
  
  int main()
  {
  	IOS;
  	int n;
  	__int128 ans;
  	while(cin >> n){
  		ans = n;
  		ans = ans*ans*25;
  		print(ans);
  	}
  
     return 0;
  }
  
  
  